LibreOffice 7.0 offers new galleries and removed the old one. If the user "update" to LibreOffice 7.0 the new galleries want be installed only the old one will be removed. When you delete the user directory, the new galleries was copied to the user home dictionary.
So the reported issue in bug 132904 would be solved by cleaning the user directory? Treat as duplicate to bug 57466?
It appears that the data for all the new galleries has been added to the installation's presets/gallery/ directory (by adding the relevant files to extras/Package_gallmytheme.mk) rather than the installation's share/gallery/ directory (by processing the relevant files via extras/Gallery_*.mk makefiles).
For example, the old arrows gallery was first removed from share/gallery/ with the commit from bug 131786 comment 3, then the new arrows gallery was added to presets/gallery/ with the commit from bug 131784 comment 2. The rationale for adding the new gallery to presets/gallery/ was presumably as given in bug 131784 comment 0: "The existing Arrows gallery offers no editable shapes so I suggest to add a new Arrow gallery with shapes that can be modified by the user."
However, without further modifications to the code, adding galleries to presets/gallery/ has the obvious drawback that they only become available when a new user installation is created from the presets/ tree.
[11:54] <htietze> sberg: Thanks for commenting on tdf#133777. What's your recommendation for 7.0?
[11:55] <sberg> htietze, my gut feeling would be that it would be best to have those galleries in share/gallery/ (which would presumably mean that they can't be edited by users), but I don't know much about the gallery code
[11:59] <sberg> htietze, in the past we utilized some "migration" code that would migrate old user installations to new ones on major version bumps, but the last time we did that was from LO 3 to LO 4 (hence still the "4" in the user installation pathname), for good reasons---that migration stuff was a nightmare in itself, so if we can get away without it, we're better off overall
[12:05] <mikekaganski> htietze: presets is a template for creation of a new profile. I would think that any modifications made into presets are *rightfully* not copied to existing profiles, which could break them
[12:06] <mikekaganski> htietze: user-modifiable galleries should be separate from bundled
[12:07] <mikekaganski> htietze: trying to bundle galleries and pretend them being modifiable will hit you the next upgrade, when an updated version of the same gallery arrives, and overwrites all user modifications
=> move new gallery content from preset/ to share/
*** This bug has been marked as a duplicate of bug 132904 ***