Just an FYI: though ubelt is a requirement for running the tests, a much more serious problem is that python-line-profiler requires an alpha version of Cython 3.0.0 to compile, and that is not (yet?) packaged for Debian. Hopefully at some point over the next two years, Cython 3.0 will mature enough to actually be released, and then it will be possible to upgrade python-line-profiler. Best wishes, Julian