Web sideloading broken on excel.cloud.microsoft - wdaddin query params stripped

[mattbrandman]

Description

office-addin-dev-settings sideload manifest.xml web no longer works when the document URL uses the new excel.cloud.microsoft domain. The wdaddindevserverport, wdaddinmanifestfile, and wdaddinmanifestguid query parameters are silently stripped by the excel.cloud.microsoft SPA during navigation.

Repro steps

1. Generate a fresh add-in with yo office --projectType taskpane --host excel --ts true
2. Run npx office-addin-dev-settings sideload manifest.xml web --app excel --document "https://excel.cloud.microsoft/open/onedrive/?docId=...&driveId=..."
3. The CLI correctly constructs the URL with query params appended:

   https://excel.cloud.microsoft/open/onedrive/?docId=...&driveId=...&wdaddindevserverport=3000&wdaddinmanifestfile=manifest.xml&wdaddinmanifestguid=...
   

4. Browser opens, but window.location.search after load only contains docId and driveId — the wdaddin* params are gone
5. Add-in does not load

Root cause (Guess)

Microsoft migrated Excel Online from *.officeapps.live.com to excel.cloud.microsoft. The new frontend is a SPA that only processes its own known query parameters (docId, driveId, etc.) and drops everything else. The wdaddin* params were previously processed server-side by the legacy officeapps.live.com rendering layer.

A quick search of this repo shows zero references to cloud.microsoft, so the tooling doesn't account for the new domain at all.

Tested with

• office-addin-dev-settings@3.0.6
• Fresh yo office generated project (also tested with a custom manifest — same result)
• macOS, Chrome (headed Playwright browser)
• Personal Microsoft account

Workaround

Manual sideloading via Home → Add-ins → More Add-ins → My Add-ins → Upload My Add-in still works on excel.cloud.microsoft.

Expected behavior

The wdaddin* query params should be forwarded to the Office Online rendering layer so that sideload web works as documented.