The files “Over-/under-expression across anatomy or life stages” has been discontinued by Bgee.

[xixilili]

bodyPartOverexpressesGene and bodyPartUnderexpressesGene are from Bgee via Hetionet. The raw data is from the file “Over-/under-expression across anatomy or life stages”, which has been discontinued.
Now, they provide a basic expression comparison tool, where you can enter gene IDs (and not gene symbols) to make a comparison based on present/absent expression calls. They have a PhD student working on how to perform differential expression analyses across conditions and species, but they don’t expect this work to be completed soon.