Android app identifier? Is there such a thing as a searchable database or a website anywhere online where someone can type in the name of an app or a package name and see a summary of what the app is for, if it is a system app, if it is just Android or iOS, list of permissions needed, etc?

I guess sort of an app dictionary/encyclopedia with more in depth info than what searching Google Play will give me.
Unlikely such a site exists and is complete. See the two links in this answer: The first currently covers 1718 apps, the second ~7,350 apps. My own site currently covers ~13,000+ apps (from multiple sources: GPlay, F-Droid, Aptoide "Apps", Xposed Repo).

Google Play covers >1 Mio apps, and I have a lot of apps not covered there (so do F-Droid (~1,800 apps) and Aptoide (~90,000 apps in their main repo, plus tons more in other "user-repos"). Then there are those apps offered outside of stores at all, e.g. only on the website of some company.

All that's left is typing the package name (surrounded by quotes) into a search box (Google, DuckDuckGo, whatever) and see what pops up. As you're specifically after malware: those results sometimes include links to scan details by several known anti-X companies, which are interesting (but not easy to read).