I like this font and the license it comes with:
> The OFL allows the licensed fonts to be used, studied, modified and redistributed freely as long as they are not sold by themselves. The fonts, including any derivative works, can be bundled, embedded, redistributed and/or sold with any software provided that any reserved names are not used by derivative works.
Very nice. I’ve paid for fonts for personal use in the past but I was always nervous about accidentally putting a screenshot or other incidental capture somewhere that might get distributed and violate the license.
The SIL Open Font License is pretty much the standard for freely releasing fonts. Poke around on Google Fonts or other places that have freely-licensed fonts and you'll find the vast majority use OFL.
Adobe's Source (the basis for this one), Google's Roboto and Google Sans, the very common Inter, Lato and Open Sans, coding/monospace fonts like Iosevka, JetBrains Mono... chances are that a free font you're aware of uses the OFL, particularly if it's even vaguely recent.
I don't believe they had a choice, since it's a derivative of Adobe's OTF-licensed Source Sans.