Storyteller's web reader is opt-in via ENABLE_WEB_READER
Configuring a self-hosted Storyteller (audiobook/ebook sync) deployment to allow in-browser synced reading without requiring the mobile app.
Storyteller's in-browser synced reader (the actual web-based read-and-listen UI, distinct from the management web UI) is disabled by default and exposed only when you set the ENABLE_WEB_READER=true environment variable on the web service in compose.yaml, then recreate the container. The Storyteller team marks the feature as experimental and asks people not to file issues against it, but it works and is the simplest way to use synced reading on a desktop without installing the Storyteller iOS/Android app or shipping the enriched EPUB3 (which Apple Books handles poorly for sideloaded files anyway). Without the env var, the management UI just doesn't expose Read / Listen buttons on book pages — easy to assume the feature doesn't exist if you only consulted the management UI.
When a self-hosted app appears to be missing a documented feature, search the docs site for experimental or enable_ env vars before assuming it's not implemented; check the project's reading/playback docs page, not just the install or management page.