There are two old app detail URLs (#11 (closed)):
-
[host]/app/[package id](https://f-droid.org/app/org.fdroid.fdroid) -
[host]/repository/browse/?fdid=[package id](https://f-droid.org/repository/browse/?fdid=org.fdroid.fdroid)
Only the first one can be redirected using HTML.
Related to #22 (closed).