The marker list brings up a text list of all of the markers and regions in the project. (Sorry, not time signature markers at the moment). Open this window by going to the View menu and selecting "Show SWS Markerlist".
You can right click in this window for options, or alternatively, check out the bottom of the main Edit menu:
The "official" Reaper forum thread is here.
If you dislike marker clutter, you can save all your markers away into a "set" which can then be recalled later.
- SWS: Open marker list Toggle showing the marker list window
- SWS: Load marker set
- SWS: Save marker set
- SWS: Delete marker set
- SWS: Copy marker set to clipboard
- SWS: Copy markers in time selection to clipboard (relative to selection start)
- SWS: Paste marker set from clipboard
- SWS: Delete all markers
- SWS: Delete all regions
- SWS: Export tracklist to clipboard Paste the list of markers to the clipboard, formatted nicely
- SWS: Tracklist format Opens a window where you can format the output of the Export tracklist action
- SWS: Select next region
- SWS: Select previous region