In the packaging data found in /debian/rules on line 10 there is:
--with-cursorpath=~/.icons:\$${datadir}/icons:/usr/share/pixmaps

This appears to include the expected ~/.icons and /usr/share/icons but not ~/.local/share/icons which is a location that modern users would expect to use for cursor themes.

I believe this is impacting other projects such as LXQt, which relies on libxcursor to determine cursor paths, causing cursor themes to not be found when placed in ~/.local/share/icons.  This undesired behavior is present in Debian 13, as well as Ubuntu 25.10 and 26.04, but is not present in non-Debian-based distros such as Fedora 44.

The "missing" themes in Debian LXQt can be made to appear by overriding the XCURSOR_PATH environment variable, further supporting the theory that the default libxcursor path list is simply missing this location.

For reference, here is the relevant bug report filed with LXQt: https://github.com/lxqt/lxqt/issues/2826#issuecomment-4896316556

My suggested change is to include ~/.local/share/icons in the cursorpath.  Whether line 10 of /debian/rules is the place to accomplish that is something that I do not have the knowledge to fully judge, but it looks like it could be.

For whatever reason, GNOME does not listen to `export
XCURSOR_PATH=$HOME/.local/share/icons:/usr/share/icons` in .bashrc.

I needed to make a symlink of ~/.icons to ~/.local/share/icons and then my
cursor theme showed up in XWayland apps. On GNOME my cursor was already
detected properly in any native Wayland application and the desktop. But on
X11 session I had a weird behavior where the desktop was default Adwaita
and opened apps were the custom cursor.