Hi. Thanks a lot for your comments.
I will leave this bug to someone more experienced about that sort of thing. (The package is QA maintained, so no special permission is required) I just wanted to answer your last question:
Has there been an archive wide rebuild of the libxaw rdepends since 1.0.16?
Yes, because I did an archive rebuild of sid on 2024-12-14, and reported everything I found two days later. So, everything that src:libxaw version 2:1.0.16-1 might have broken is almost surely already reported. Thanks.