What are spam requests?

Question

Information Security

At first, the /robots.txt request came to the server, then after a couple of minutes a bunch of different requests rained down:

Screen

The search engine indexed my site, after which it appeared in the database of some kind of script that checks for vulnerabilities?

Answer 1

That's right, bots scan the site for vulnerabilities (if you don't have such pages and many requests get 404). This is fine.
Close the holes before you are broken.

Answer 2

Well, this is indexing and possibly other people's bots