private FileCacheEntry getFileByMD5(String md5) {
		File f = new File(cacheDir, getCacheRelPath(md5));
		return f.exists() ? new FileCacheEntry(f, md5) : null;
	}
Get a file (by md5) from the cache, returns NULL if not found.

@param md5 file md5 string.
@return File or null if not found.
Ghidra/Features/Base/src/main/java/ghidra/formats/gfilesystem/FileCache.java