JetBrains Mono typeface (https://www.jetbrains.com/lp/mono/) is available under the SIL Open Font License 1.1 and can be used free of charge, for both commercial and non-commercial purposes. You do not need to give credit to JetBrains, although we will appreciate it very much if you do. Licence: https://github.com/JetBrains/JetBrainsMono/blob/master/OFL.txt