Supported font formats

So I’ve been searching, and haven’t found anything about this.
What font formats are supported and able to be loaded into the engine? Is it only .ttf (TrueType Format), or is .otf (OpenType Format) supported as well?

Nvm, found out that it only supports .ttf since it locks used .ttf files but none of the .otf files get locked.
It’s a shame, since some fonts are only .otf and converting it to .ttf results in degradation of its quality.