linear gradients

Question

Is the vendor prefix necessary in the gradients, or is it necessary only to unsupported browsers?

Answer 1

Web browsers are developed all the time to meet the latest standards. But many people still use old versions of browsers that may be lagging behind. Part of a web developer's job is to ensure that their code and stylesheet is working properly on as many different platforms as possible - or you can say that your website does not support x or y browser... and potentially lose some viewers :)
Anyway google is your best friend to research these compatibility issues, because the SoloLearn lessons are actually a bit outdated in this regard.
https://www.lambdatest.com/blog/complete-guide-to-cross-browser-compatible-css-gradients/