I would imagine it depends a lot on how you quantify things, there's all sorts of procedural votes and "renaming a post office" bills with no real substance that you could reasonably argue should or shouldn't be included, to say nothing of ranking the partisan quality of different legislation (like, if Sanders and Harris both voted the same way in a routine budget bill that got unanimous support, should that count the same as them voting the same on some legislation he sponsored that failed or something?).

That all said, this CNN article I found from 2020 makes it sound more true than not, but there's some nuance - tl;dr, at the start of her career as a state AG she did some more conservativ-ish things, but she's been consistently more and more progressive since then.

My personal opinion is that she's willing to change her positions a lot if she thinks that's where voters are going, which isn't perfect, but it's a lot better than the last generation of Democratic leaders who are also willing to change their positions a lot but think voters are way more conservative than they actually are (because that generation is still stuck in the 1980s). Kamala didn't start talking about Medicare for All until Bernie made it popular, but when he did she didn't have a problem jumping on board (unlike Biden, who would only ever go as far as public option).