Select Muted Channel Strips    ⇧M

Selects all muted channel strips.

Has priority over ‘Select Muted Regions/Cells/Events ⇧M’ in — Main Window Tracks and Various Editors

Mute and solo channel strips in Logic Pro — Apple Support

You can silence (mute) a channel strip so that you don’t hear it when you play the project. Muting channel strips is useful when you want to compare how the project sounds with and without the target track, compare alternative versions of a track, or try different loops in a project.