The Project Explorer view in Eclipse shows the projects and their files. By default, some files are hidden. But I can change that, and I can hide and unhide files based on rules:

To hide or unhide (or filter) files and folders, the Project Explorer view has an icon for it:

It is accessible with a menu item here:

It comes with a set of pre-set filters I can enable or disable:

With the default filters, files like .project or .cproject are hidden (.* resources).
In the ‘User filters’ settings I can add my custom filters to filter files and folders:

Finaly, I can filter by the content:

That way I can extend or customize the filters and what I see in the Project Explorer view.
Happy filtering 🙂