There are also many languages that I would consider "supplementary", and Perl would be a good example. There are a few jobs where it's the main language but mos

There are also many languages that I would consider "supplementary", and Perl would be a good example. There are a few jobs where it's the main language but most listings I see have it as a nice-to-have or side skill language for things like a Devops hire that wants some kind of scripting but doesn't really care what (listed as an option alongside Python, Ruby, etc). So in particular I'd say Perl is pervasive, but not a hiring differential. At least that's my experience looking at jobs.