What are the EOT and WOFF formats for in fonts?

Question

Fonts

Always noticed these extensions, but did not download them, because. it seemed to me that ttf is the basis for the web.
And then I came across a guide where all 3 extensions are downloaded into the project.

Answer 1

eot - for older versions of Internet Explorer
woff and woff2 - modern web font formats (weight less than ttf)
woff2 is more modern and weights even less than woff, but less support in older browsers
https://caniuse.com/#search= eot
https://caniuse.com/#search=ttf
https://caniuse.com/#search=woff
https://caniuse.com/#search=woff2