EPUB conformance profile ignored in WebPub manifests

[sysint64]

Describe the bug

When loading a WebPub manifest that declares conformance to the EPUB profile via "conformsTo": "https://readium.org/webpub-manifest/profiles/epub", the publication does not behave like an EPUB. Instead, it's treated as a standard WebPub with limited functionality.

Issues observed

1. No user preferences available e.g.: Theme selection, letter spacing, text alignment, etc.
2. Location tracking behaves like WebPub instead of EPUB:
   • Location updates only trigger on full page changes
   • No location updates during in-page scrolling

Environment

• Confirmed in: Readium Test App
• Works correctly in: Throium Web

Example

Moby Dick on the publication server demonstrates the issue:
https://publication-server.readium.org/Z3M6Ly9yZWFkaXVtLXBsYXlncm91bmQtZmlsZXMvZGVtby9tb2J5LWRpY2suZXB1Yg/manifest.json

How to reproduce?

1. Load a WebPub manifest with the EPUB profile declaration, e.g. https://publication-server.readium.org/Z3M6Ly9yZWFkaXVtLXBsYXlncm91bmQtZmlsZXMvZGVtby9tb2J5LWRpY2suZXB1Yg/manifest.json
2. Open the publication
3. Attempt to submit user preferences (it's not available on Redium Test App UI at all)
4. Observe location update behavior while scrolling

Readium version

3.1.2

Android API version

Android 15 (API level 35)

Additional context

No response