public synchronized void closeAllUnused() {
		List<FSCacheInfo> recsToPurge = getUnusedFSes();
		if (!recsToPurge.isEmpty()) {
			Msg.info(this, "Removing " + recsToPurge.size() + " unused filesystems from cache");
		}
		for (FSCacheInfo fsci : recsToPurge) {
			release(fsci);
		}
	}
Removes any unused filesystems in the cache.
Ghidra/Features/Base/src/main/java/ghidra/formats/gfilesystem/FileSystemInstanceManager.java