A variety of library parts are not directly placeable by tools and/or selectable, and thus it is trickier to open them for examination or modification.
File > Libraries and Objects > Open Object by Subtype ...
can give you a dialog similar to the one attached for the US library. Open the Story Marker, modify and Save As into your company or project library folder....
(If the command above does not appear in your menus, you may have to add it via the Work Environment.)
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB