This link does not contain FontBase itself, so it should be fine to share. It's just a program that disables the subscription check.

https://gist.githubusercontent.com/tkito16/de4be3b416d4428227851419f2dae009/raw/fontbase-crack.py

1. Install FontBase
2. Install Python
3. Save the above Python script as a file (keep the .py extension)
4. As with all downloaded scripts, check the script to ensure it is not doing anything malicious
5. Execute it (python3 fontbase-crack)
6. Restart FontBase