Welcome to the forums. I can't speak with 100% certainty on this because I'm not a developer, but I found this article explaining what the manifest file is for.
https://developer.android.com/guide/topics/manifest/manifest-intro
Long story short, they are legit files that normally shouldn't be seen or accessed by end users. They are meant to work in the background. As to why you are seeing a "new" and "old" file may be to do with how the developer of that associated app keeps track of their updates, but that's just speculation.
What I do know is that it's rather hard to hack into Android, and document recovery apps have a habit of showing every little thing it can find, even files it honestly has no need or business pulling up for you.
For now, I wouldn't worry. There's a lot of stuff that goes on in the background and lots of files a user could access with a little digging that only look suspicious. For example, LG phones have an app with the name "informant" in it that is used by a widget to work right. Normally this app is not visible, but many times people looking for a problem that doesn't exist will find it and immediately think the FBI is spying on them. Actual hackers and malware would not make their presence so easily discovered.