To nitpick even more, gawk (GNU Awk) is a superset of POSIX Awk. I'm not very familiar with the differences, but I always use specifically gawk---I got too annoyed with some of the BSD userland that ships with macOS, and learned to prefer GNU versions.

Besides mawk and gawk, Debian ships also the original awk:

https://www.cs.princeton.edu/~bwk/btl.mirror/

Yes, and it works well on Debian. But I can't recommend switching to gawk on Ubuntu.

[1]: https://askubuntu.com/questions/1011414/gawk-is-crashing-for...