Linting is the process of alerting programmers of "lint" in the code which just means that there is a certain style the code should be written in and if you are writing it in some other way a linting tool will highlight how you should write it to stay consistent with how other programmers are writing code on the project you are working on.
The goal of this process is to write code that looks the same across the entire project.
All big projects are likely using a linter tool.
At the time of writing this document the following linters are very common: