Saved places
Up to fifty places, stored on this device. Rename them to whatever is useful to you, and copy a link if you want to send somebody the whole set.
Reading your browser…
Naming things properly
A saved place keeps whatever the address lookup returned, which is often a street number and a postcode. That is fine for one or two and useless for forty. Rename them to what they actually are to you, because a list of your own labels is far easier to scan than a list of addresses.
Sharing a collection
The share button packs every saved place into a single link. Nothing is uploaded: the coordinates travel inside the link itself, so whoever opens it sees your list without any of it passing through a server.
Why there is a limit
Fifty, because browser storage is finite and a list longer than that stops being a shortlist. If you are up against it, the history page keeps a rolling record of everywhere you have been, and it can be exported as a spreadsheet.