JetBrains Mono is one typeface, not a collection: a monospace font built by JetBrains for its own IDEs and released to everyone else too.
The point is legibility in a code editor specifically - taller lowercase letters, a dotted zero, and ligatures for things like => and != so operators do not turn into visual noise.
Good fit if you are picking a font for your terminal or code editor and do not want to pay for one.
SIL Open Font License 1.1 - free, open source, no commercial restrictions.
