I must admit I hadn’t heard of glob patterns until seeing some settings in VS Code that use them. They are a way of defining a pattern that matches one or more files and folders. For example, the Text Editor section of the settings (UI) in VS Code allows you to exclude files and folders from the file explorer with glob patterns and gives you this useful link for more information.
My AL Test Runner extension has a glob pattern setting to identify your test codeunits (used when identifying the file path and line number of a failing test to give you a clickable link in the output window).
Turns out that glob patterns are case-sensitive. You can, however, match from a group of characters (like regular expressions) with square brackets. Useful if you’ve got inconsistently named files. My Test Codeunit Glob Pattern setting (in AL Test Runner) is set to **Tests/*.[cC]odeunit.al i.e. match files in a Tests folder which end with either codeunit.al or Codeunit.al