Greg Wolanski (@gregwolanski.com) believes in [OPML] files:

I follow various websites using RSS. The list of sites I follow is a single OPML file that I can import to any RSS reader. Thanks to this single file, I don’t have to worry about being forced to use a specific app or painstakingly import my list of followed sites into a new one.

Subscription lists are an excellent example of the evergreen "File over app" principle by Steph Ango (@stephango.com), the CEO of @obsidian.md.

If you have ever exported your podcast subscriptions from a podcast app and taken them with you to a new podcast app, then you have very likely used an #OPML file.

Did you know that @hypertexting.com supports OPML file import and export, and podcast feeds? Just tap "Explore", then tap the "..." button and choose "Import feeds".