Quoting https://thenieveslawfirm.com/do-police-have-to-identify-them...:

You’re minding your own business when a police officer approaches you. They start asking questions, but something feels off. You ask for their name and badge number, but they refuse. What do you do?

As a citizen, you want to trust and cooperate with law enforcement, but you also have rights that must be protected. The question of whether police officers are legally required to identify themselves when asked is a complex one, with no easy answers.

In general, no, a police officer does not have to identify themselves even if you ask them—making it even more important to invoke your right to silence no matter who you think you’re talking to.

California Penal Code Section 830.10 states:

“Any uniformed peace officer shall wear a badge, nameplate, or other device which bears clearly on its face the identification number or name of the officer.”

However, there are a couple of key issues with this law that limit its effectiveness in ensuring police accountability:

    The law only applies to uniformed officers, meaning that plainclothes officers or those working undercover are not required to wear any identifying information.
    Even for uniformed officers, the law doesn’t explicitly require them to make their badge number or name easily visible or accessible to the public. An officer could potentially wear their identifying information in a manner that is obscured or difficult to read.

> An officer could potentially wear their identifying information in a manner that is obscured or difficult to read.

Yeah... but they could also not wear a badge. I doubt that'll fly

> or other device which bears clearly on its face the identification number or name of the officer.

Any reasonable court would find that wearing a badge in a manner that obscured the number or name would not be "clearly wearing" said badge. Is the officer an ethical person who makes a good faith attempt to follow the law they're hired to uphold, and will the court be reasonable are both questions that don't change what the law clearly expects and requires.