The Ubuntu file browser does not show hidden files or folders by default.Here is the solution how to view Hidden Files and Folders in Ubuntu File Browser.
Here’s what file browser looks like when browsing the root file system normally
As you can see, all of the hidden/system folders are not shown. If you hit Ctrl+H at this screen, you will immediately see all the hidden files.
If you would just prefer to make this be the default setting when using file browser, go to the Edit menu and select Preferences
Check the “Show hidden and backup files” checkbox, and you should now see the hidden files all of the time.