The static library implementing this backend. This environment variable specifies the list of directories that may contain the configuration file. If the value of the environment variable ends with the directory separator character, then the default directories are searched after the explicitly spec ified directories. If the library was compiled with debug support enabled, this environment variable controls the debug level for this backend. E.g., a value of 128 requests all debug output to be printed.
Smaller levels reduce verbosity.
This variable sets the debug level for the SANE interface for the Mustek chipset A4S2. Note that enabling this will spam your terminal with some million lines of debug output. If something doesn't work, please contact me. Please also include the optical resolution and lamp type of your scanner, both can be found in the manual of your scanner.