Gimp pandora plugin
Pandora is a plugin for the Gimp image manipulation program. It can be used to assemble panoramic multilayer images:
Call it up from Xtns -> Make Panorama give it a list of files, in order, and an average overlap, and it will give you an image big enough to hold all the pieces, with all the component pieces overlapped to the specified amount, and with gradient layer masks so they fade into each other.
Even this is a old plugin, it still works with Gimp 2.10.