If your custom protocol (e.g. web+collab) stopped working after an update, it might be because some Chrome flags got reset. You can re-enable them as follows:

1. Open chrome://flags in your browser.

2. Search for web-app-manifest-protocol-handlers and set it to Enabled.

3. Search for isolated and enable the required flags.

4. Open chrome://policies and click Reload policies.

That’s it! Your custom protocol (web+collab) should now work again.