Author here. No architecture specific processing currently. Most of the magic happens in zstandard (hat tip to this amazing project).

Please see our new applicability section which explains the result in a bit more detail:

https://github.com/elfshaker/elfshaker/blob/1bedd4eacd3ddd83...

In manyclangs (which uses elfshaker for storage) we arrange that the object code has stable addresses when you do insertions/deletions, which means you don't need such a filter. But today I learned about such filters, so thanks for sharing your question!