Wordpress export file questions

I just have a general question or two about how the Wordpress export process works. I downloaded the WXR file which is a bit over 2mb in size. I used the mpmilestogo.micro.blog domain for awhile and then switched to mpmilestogo.me. If I use the export file to test on a self hosted Wordpress site, how exactly does this work? It appears from looking at the WXR file it uses RSS to grab everything. Will it grab all posts and images from both domains on micro.blog? When I import the file does it just use the existing site to grab all the stuff? I think it does. I could not find any particular posts on help about how the process works. I would just like to test the existing site on Wordpress and see if all my posts since 2019 are exported and then imported to Wordpress with images intact.

Yes, because the WXR file format does not include images, WordPress should try to download them from your current site. That’s how Micro.blog’s import works. Probably best to try it out on a test WordPress blog… WXR was developed by the WordPress folks so we just try to support it as best we can, but the import itself in WordPress is outside of what Micro.blog has control over.