They mean fishing for CVs.

Many recruiters invent roles so that they can build a database of CVs.

Invent roles, or straight up lie. The giveaway is usually that they want a call with you to discuss details, or can’t produce any job description.

...or they have a 1+ year long 'open position' so they always have an infinite pool of applicants.

In fact, this is most recruiter inquiries.