Got a few recent calls from this Belvedere Ti CA number, after getting and blocking many calls over a year ago. I had removed this number from my blocklist to make room for other numbers, but now they are calling again. However, now I have an online blocker which automatically terminated this call after 1 ring - based on searching databases of complaints and high call volumes during the first ring for every incoming call. Although the scammers are scrambling by having some autodialers switch numbers on every call, they will fail if most of us targets have online blocking and promptly report scam numbers so they are blocked by everyone and hence useless.
Similar thing here. they kept calling and tonight I finally answered. The woman asked for my wife by name. I said she was busy and asked what this was about. The caller was super cagey and kept trying stating it just simple questions about infrastructure. Eventually asked them to take our details out of their DB and they hung up.
This 415-691-8036 caller is one of many criminals who search for people who answer calls from anonymous callers so they can sell your number on the dark web to con men who will call you to try to scam you.