QgsProcessingParameterMultipleLayers|maps|Raster maps used in the calculator|3|None|True
QgsProcessingParameterString|expression|Expression to evaluate. Syntax e.g. `raster_out=raster1+raster2`. Use original filenames, without extension|None|True|True
QgsProcessingParameterFile|file|File containing expression(s) to evaluate (same rule for raster names than above)|QgsProcessingParameterFile.File|txt|None|True