FLAC (Free Lossless Audio Codec) files aren’t as popular for playing audio as MP3 files, but FLAC files do offer better audio quality than MP3 files. When audio was first being downloaded from the Internet back in the 1990s, MP3 files were chosen because they offered good quality, but more important, small file sizes. Back when people were connecting to the Internet through dial-up modems, smaller file sizes were preferred. I remember waiting 15 minutes while a 3 MB MP3 file downloaded.
These days, high-speed Internet connections are more the norm, so downloading a 30 MB file can take less than a minute. Because of this, many people have started to switch from downloading MP3 files to FLAC files.