Optimizations for XML file search
With support for versioned XML files, the searching for all possible XML files can now take quite some time (depending on mounted directories, etc). One way to improve the situation could be to rely on or own file searching as implemented in MeteoIO (see https://code.wsl.ch/snow-models/meteoio/-/blame/master/meteoio/FileUtils.cc?ref_type=heads#L269). As this only retrieves file names and skips all other metadata, it is much, much faster than a standard file search (in pathological cases such as a network directory with 100k files, retrieving a list of files matching a specific pattern went from ~10 minutes down to a few seconds).
By the way, if this works it could also be suggested to Qt...