diff --git a/packages/extension-dapp/src/compat/index.ts b/packages/extension-dapp/src/compat/index.ts
index dcfe3a09..c8c26fda 100644
--- a/packages/extension-dapp/src/compat/index.ts
+++ b/packages/extension-dapp/src/compat/index.ts
@@ -1,14 +1,12 @@
 // Copyright 2019-2021 @polkadot/extension-dapp authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import initMetaMaskSource from './metaMaskSource';
-import singleSource from './singleSource';
+import initMetaMask from './metamask';
 
 // initialize all the compatibility engines
 export default function initCompat (): Promise<boolean> {
   return Promise.all([
-    singleSource(),
-    initMetaMaskSource()
+    initMetaMask()
   ]).then((): boolean => {
     return true;
   });
diff --git a/packages/extension-dapp/src/compat/metaMaskSource.ts b/packages/extension-dapp/src/compat/metamask.ts
similarity index 66%
rename from packages/extension-dapp/src/compat/metaMaskSource.ts
rename to packages/extension-dapp/src/compat/metamask.ts
index 88412b0f..0af40d40 100644
--- a/packages/extension-dapp/src/compat/metaMaskSource.ts
+++ b/packages/extension-dapp/src/compat/metamask.ts
@@ -7,6 +7,7 @@ import detectEthereumProvider from '@metamask/detect-provider';
 import Web3 from 'web3';
 
 import { SignerPayloadRaw, SignerResult } from '@polkadot/types/types';
+import { assert } from '@polkadot/util';
 
 interface RequestArguments {
   method: string;
@@ -18,29 +19,29 @@ interface EthRpcSubscription {
 }
 
 interface EthereumProvider {
-  request: (args: RequestArguments) => Promise<any>;
+  request: (args: RequestArguments) => Promise<unknown>;
   isMetaMask: boolean;
-  on: (name: string, cb: any) => EthRpcSubscription;
+  on: (name: string, cb: (value: unknown) => void) => EthRpcSubscription;
 }
 
 interface Web3Window extends InjectedWindow {
   // this is injected by metaMask
-  ethereum: any;
+  ethereum: unknown;
 }
 
 function isMetaMaskProvider (prov: unknown): EthereumProvider {
-  if (prov !== null) {
-    return (prov as EthereumProvider);
-  } else {
-    throw new Error('Injected provider is not MetaMask');
-  }
+  assert(prov && (prov as EthereumProvider).isMetaMask, 'Injected provider is not MetaMask');
+
+  return (prov as EthereumProvider);
 }
 
-// transfor the Web3 accounts into a simple address/name array
+// transform the Web3 accounts into a simple address/name array
 function transformAccounts (accounts: string[]): InjectedAccount[] {
-  return accounts.map((acc, i) => {
-    return { address: acc, name: 'MetaMask Address #' + i.toString(), type: 'ethereum' };
-  });
+  return accounts.map((address, i) => ({
+    address,
+    name: `MetaMask Address #${i}`,
+    type: 'ethereum'
+  }));
 }
 
 // add a compat interface of metaMaskSource to window.injectedWeb3
@@ -56,11 +57,13 @@ function injectMetaMaskWeb3 (win: Web3Window): void {
       return {
         accounts: {
           get: async (): Promise<InjectedAccount[]> => {
-            return transformAccounts(await provider.request({ method: 'eth_requestAccounts' }));
+            const response = await provider.request({ method: 'eth_requestAccounts' });
+
+            return transformAccounts(response as string[]);
           },
           subscribe: (cb: (accounts: InjectedAccount[]) => void): (() => void) => {
-            const sub = provider.on('accountsChanged', function (accounts: string[]) {
-              cb(transformAccounts(accounts));
+            const sub = provider.on('accountsChanged', (accounts): void => {
+              cb(transformAccounts(accounts as string[]));
             });
             // TODO: add onchainchanged
 
@@ -71,9 +74,9 @@ function injectMetaMaskWeb3 (win: Web3Window): void {
         },
         signer: {
           signRaw: async (raw: SignerPayloadRaw): Promise<SignerResult> => {
-            const signature = (await provider.request({ method: 'eth_sign', params: [raw.address, Web3.utils.sha3(raw.data)] }) as string);
+            const signature = await provider.request({ method: 'eth_sign', params: [raw.address, Web3.utils.sha3(raw.data)] });
 
-            return { id: 0, signature };
+            return { id: 0, signature: signature as string };
           }
         }
       };
@@ -82,8 +85,6 @@ function injectMetaMaskWeb3 (win: Web3Window): void {
   };
 }
 
-// returns the MetaMask source instance, as per
-// https://github.com/cennznet/singlesource-extension/blob/f7cb35b54e820bf46339f6b88ffede1b8e140de0/react-example/src/App.js#L19
 export default function initMetaMaskSource (): Promise<boolean> {
   return new Promise((resolve): void => {
     const win = window as Window & Web3Window;
diff --git a/packages/extension-dapp/src/compat/singleSource.ts b/packages/extension-dapp/src/compat/singleSource.ts
deleted file mode 100644
index c482da21..00000000
--- a/packages/extension-dapp/src/compat/singleSource.ts
+++ /dev/null
@@ -1,85 +0,0 @@
-// Copyright 2019-2021 @polkadot/extension-dapp authors & contributors
-// SPDX-License-Identifier: Apache-2.0
-
-import type { Signer } from '@polkadot/api/types';
-import type { Injected, InjectedAccount, InjectedWindow } from '@polkadot/extension-inject/types';
-
-// RxJs interface, only the bare-bones of what we need here
-interface Subscriber<T> {
-  subscribe: (cb: (value: T) => void) => {
-    unsubscribe (): void;
-  };
-}
-
-interface SingleSourceAccount {
-  address: string;
-  assets: { assetId: number }[];
-  name: string;
-}
-
-interface SingleSource {
-  accounts$: Subscriber<SingleSourceAccount[]>;
-  environment$: string[];
-  signer: Signer;
-}
-
-interface SingleWindow extends InjectedWindow {
-  SingleSource: SingleSource;
-}
-
-// transform the SingleSource accounts into a simple address/name array
-function transformAccounts (accounts: SingleSourceAccount[]): InjectedAccount[] {
-  return accounts.map(({ address, name }): InjectedAccount => ({
-    address,
-    name
-  }));
-}
-
-// add a compat interface of SingleSource to window.injectedWeb3
-function injectSingleSource (win: SingleWindow): void {
-  let accounts: InjectedAccount[] = [];
-
-  // we don't yet have an accounts subscribe on the interface, simply get the
-  // accounts and store them, any get will resolve the last found values
-  win.SingleSource.accounts$.subscribe((_accounts): void => {
-    accounts = transformAccounts(_accounts);
-  });
-
-  // decorate the compat interface
-  win.injectedWeb3.SingleSource = {
-    // eslint-disable-next-line @typescript-eslint/no-unused-vars,@typescript-eslint/require-await
-    enable: async (origin: string): Promise<Injected> => ({
-      accounts: {
-        // eslint-disable-next-line @typescript-eslint/require-await
-        get: async (): Promise<InjectedAccount[]> =>
-          accounts,
-        subscribe: (cb: (accounts: InjectedAccount[]) => void): () => void => {
-          const sub = win.SingleSource.accounts$.subscribe((accounts): void => {
-            cb(transformAccounts(accounts));
-          });
-
-          return (): void => {
-            sub.unsubscribe();
-          };
-        }
-      },
-      signer: win.SingleSource.signer
-    }),
-    version: '0.0.0'
-  };
-}
-
-// returns the SingleSource instance, as per
-// https://github.com/cennznet/singlesource-extension/blob/f7cb35b54e820bf46339f6b88ffede1b8e140de0/react-example/src/App.js#L19
-export default function initSingleSource (): Promise<boolean> {
-  return new Promise((resolve): void => {
-    const win = window as Window & SingleWindow;
-
-    if (win.SingleSource) {
-      injectSingleSource(win);
-      resolve(true);
-    } else {
-      resolve(false);
-    }
-  });
-}
diff --git a/packages/extension-dapp/src/index.ts b/packages/extension-dapp/src/index.ts
index 55242ea6..5beccf7c 100644
--- a/packages/extension-dapp/src/index.ts
+++ b/packages/extension-dapp/src/index.ts
@@ -73,35 +73,30 @@ export function web3Enable (originName: string): Promise<InjectedExtension[]> {
     (): Promise<InjectedExtension[]> =>
       initCompat().then(() =>
         getWindowExtensions(originName)
-          .then((values): InjectedExtension[] => {
-            return values
+          .then((values): InjectedExtension[] =>
+            values
               .filter((value): value is [InjectedExtensionInfo, Injected] => !!value[1])
-              .map(
-                ([info, ext]): InjectedExtension => {
-                  // if we don't have an accounts subscriber, add a single-shot version
-                  if (!ext.accounts.subscribe) {
-                    ext.accounts.subscribe = (cb: (accounts: InjectedAccount[]) => void | Promise<void>): Unsubcall => {
-                      ext.accounts.get().then(cb).catch(console.error);
+              .map(([info, ext]): InjectedExtension => {
+                // if we don't have an accounts subscriber, add a single-shot version
+                if (!ext.accounts.subscribe) {
+                  ext.accounts.subscribe = (cb: (accounts: InjectedAccount[]) => void | Promise<void>): Unsubcall => {
+                    ext.accounts.get().then(cb).catch(console.error);
 
-                      return (): void => {
-                        // no ubsubscribe needed, this is a single-shot
-                      };
+                    return (): void => {
+                      // no ubsubscribe needed, this is a single-shot
                     };
-                  }
-
-                  return { ...info, ...ext };
+                  };
                 }
-              );
-          }
+
+                return { ...info, ...ext };
+              })
           )
           .catch((): InjectedExtension[] => [])
           .then((values): InjectedExtension[] => {
             const names = values.map(({ name, version }): string => `${name}/${version}`);
 
             isWeb3Injected = web3IsInjected();
-            console.log(
-              `web3Enable: Enabled ${values.length} extension${values.length !== 1 ? 's' : ''}: ${names.join(', ')}`
-            );
+            console.log(`web3Enable: Enabled ${values.length} extension${values.length !== 1 ? 's' : ''}: ${names.join(', ')}`);
 
             return values;
           })
@@ -111,7 +106,7 @@ export function web3Enable (originName: string): Promise<InjectedExtension[]> {
   return web3EnablePromise;
 }
 
-// retrieve all the accounts accross all providers
+// retrieve all the accounts across all providers
 export async function web3Accounts ({ accountType, ss58Format }: Web3AccountsOptions = {}): Promise<InjectedAccountWithMeta[]> {
   if (!web3EnablePromise) {
     return throwError('web3Accounts');
@@ -121,37 +116,30 @@ export async function web3Accounts ({ accountType, ss58Format }: Web3AccountsOpt
   const injected = await web3EnablePromise;
 
   const retrieved = await Promise.all(
-    injected.map(
-      async ({ accounts, name: source }): Promise<InjectedAccountWithMeta[]> => {
-        try {
-          const list = await accounts.get();
+    injected.map(async ({ accounts, name: source }): Promise<InjectedAccountWithMeta[]> => {
+      try {
+        const list = await accounts.get();
 
-          return mapAccounts(source, list.filter((acc) => acc.type && accountType ? accountType.includes(acc.type) : true), ss58Format);
-        } catch (error) {
-          // cannot handle this one
-          return [];
-        }
+        return mapAccounts(source, list.filter(({ type }) => type && accountType ? accountType.includes(type) : true), ss58Format);
+      } catch (error) {
+        // cannot handle this one
+        return [];
       }
-    )
+    })
   );
 
   retrieved.forEach((result): void => {
     accounts.push(...result);
   });
 
-  const addresses = accounts.map(({ address }): string => address);
+  const addresses = accounts.map(({ address }) => address);
 
-  console.log(
-    `web3Accounts: Found ${accounts.length} address${accounts.length !== 1 ? 'es' : ''}: ${addresses.join(', ')}`
-  );
+  console.log(`web3Accounts: Found ${accounts.length} address${accounts.length !== 1 ? 'es' : ''}: ${addresses.join(', ')}`);
 
   return accounts;
 }
 
-export async function web3AccountsSubscribe (
-  cb: (accounts: InjectedAccountWithMeta[]) => void | Promise<void>,
-  { ss58Format }: Web3AccountsOptions = {}
-): Promise<Unsubcall> {
+export async function web3AccountsSubscribe (cb: (accounts: InjectedAccountWithMeta[]) => void | Promise<void>, { ss58Format }: Web3AccountsOptions = {}): Promise<Unsubcall> {
   if (!web3EnablePromise) {
     return throwError('web3AccountsSubscribe');
   }