Studio: Fix Microsoft Store login by adding protocol handler to AppxManifest

[bcotrim]

Related issues

• Fixes STU-927

Proposed Changes

• Add addProtocolHandlerToManifest to existing app manifest

Testing Instructions

1. Download the signed .appx file from the CI build artifacts for this PR
2. Install the .appx on a Windows machine (right click -> Install)
3. Open Studio and click the "Login" button in the top right
4. Authenticate in the browser when redirected to WordPress.com
5. After approving, verify the browser shows "Authorized. You can now open Studio and close this window."
6. Verify Studio successfully logs you in and displays your account information

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[ivan-ottinger]

Thanks for the changes, Bernardo. This helps the Blueprints from everywhere project as well!

I see the auth deeplink now works correctly with the changes to the AppxManifest:

Screen.Capture.on.2025-10-30.at.11-12-52.mp4

The proposed changes look good to me. I just need to note that this is the first time I am reviewing this kind of updates to the manifest file so it would be worth having a second pair of eyes on this as well.

[epeicher]

Thanks @bcotrim! I have tested this on Windows and it works as described, I have been able to log-in with this version of the appx. LGTM!

[wojtekn]

@bcotrim looks good, however, let's update description as it doensn't match the current changes.

@twstokes do you think we should implement it in our fork (https://github.com/Automattic/electron-windows-store) at some point?

[github-actions]

📊 Performance Test Results

Comparing 67a0999 vs trunk

site-editor

Metric	trunk	67a0999	Diff	Change
load	13314.00 ms	11291.00 ms	-2023.00 ms	🟢 -15.2%

site-startup

Metric	trunk	67a0999	Diff	Change
siteCreation	23502.00 ms	22167.00 ms	-1335.00 ms	🟢 -5.7%
siteStartup	7001.00 ms	7027.00 ms	+26.00 ms	🔴 0.4%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change

[twstokes]

@twstokes do you think we should implement it in our fork (https://github.com/Automattic/electron-windows-store) at some point?

@wojtekn I hope that we don't have to keep the fork around for a long time, but please feel free to own any updates to the fork that you see fit. We can grant whatever permissions you may need to the repo. Thanks!