After debugging some more, I found even an old dh-python to show the problem, and I see this:
- Bug#1127763: dh-python: regression in build of ... Gianfranco Costamagna
- Bug#1127763: wheel regression? Gianfranco Costamagna
- Bug#1127763: wheel issue? Gianfranco Costamagna
- Bug#1127763: a package in sid is already a... Gianfranco Costamagna
- Bug#1127763: a package in sid is alrea... Stefano Rivera
- Bug#1127763: a package in sid is a... Gianfranco Costamagna
- Bug#1127763: Followup: Can't build cocotb ... أحمد المحمودي
- Bug#1127763: Followup: Can't build cocotb ... أحمد المحمودي
- Bug#1127763: marked as pending in dh-pytho... Stefano Rivera
- Processed: Bug#1127763 marked as pending i... Debian Bug Tracking System
- Bug#1127763: Please try setting DEB_BUILD_... أحمد المحمودي
