Inkscape font list cache: forcing a rebuild after installing new system fonts

Inkscape builds a cache of available system fonts at startup, so fonts installed while the system is running may not appear in the Text tool's font family dropdown. I want a reliable way to make Inkscape pick up newly installed fonts without losing my other customizations.

My understanding is that the font cache lives in the user profile or cache directory (for example ~/.cache/inkscape on Linux, %APPDATA%\inkscape on Windows), and that deleting it forces a rebuild on next launch. What is unclear is the boundary between Inkscape's own cache and the fontconfig cache on Linux, and whether sandboxed installs (Flatpak/Snap) change the paths. I also want to avoid wiping preferences.xml, custom palettes, and templates along with the cache. Assume a current stable Inkscape release; exact paths may vary by OS and packaging.

Which specific files or subdirectories inside the Inkscape profile hold the font list cache, so they can be removed in isolation? On Linux, does Inkscape rely on fontconfig's cache, meaning both layers may need refreshing? Is there any supported in-application way to invalidate the font cache short of deleting files while Inkscape is closed?