TCL modules are still pretty widely used in HPC-like environments unfortunately:

https://modules.readthedocs.io/en/stable/modulefile.html

Though there is a replacement that uses Lua which is somewhat better than TCL:

https://lmod.readthedocs.io/en/latest/index.html

TCL is also pretty universally used in EDA scripting. It's pretty bad, though I guess it is better than all the Bash that EDA devs tend to use too.