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 255 requests all debug output to be printed.
Smaller levels reduce verbosity.
There are a few known ones, and definitely some unknown ones. Therefore, it may not be possible to scan to the extreme right or bottom edges of the page. Cancelling the scan This might not work correctly, or it might abort the frontend. The former is more likely than the latter.