Ah. Okay cool. Finally got this working.

Using the source url:
https://www.torproject.org/download

And adding a custom APK Link Filter with a regexp:

(.*)\-arch\-(.*).apk$

Replacing arch with the available options: aarch64, arm, x86_64 or x86. 

 Was this done in obtainium? 

 Yeah 

 I keep getting errors 

 Got it by removing the - in front of aarch64 

 Cool. I also added that regexp to Version String Extraction and $2 as the match group. Gives a version number instead of the hash. 

 Dope! Thanks. I have wanted to get Tor into Obtainium for a while.