I don't know why the OP is a screenshot of github that is linked to github. Maybe it is some new kind of link bait. Here is the content --

"But I really feel like these extensionless files are a bad idea for usability. They look odd in Windows explorer, and they break Quicklook on Mac.

An extension ‘txt’ also informs novice users about the role of these files: they are not programming code, they are primarily meant to be read."