The huge version of #Fedilab (3.31.1) was compiled by #FDroid. We are sorry for that, we thought to have made everything to avoid that (3.31.1 exists in a smaller release).
This important difference in size is due to the use of a library that allows to locally detect the language used in a message. We needed it for MinT translator that doesn't support auto detection.
We immediately removed this lib and we used the language attached to a message (though it is not perfect)

Really sorry for that