Please help- Permissions for Dark Mode For Safari- what's up with this?

I'm assuming we're talking about this Dark Mode for Safari app, which contains a Safari extension.

The app's privacy policy explicitly and clearly states that they don't collect any personal information, passwords or anything of the like:

• Our Safari extensions are not collecting or accessing any information from your browser, user clicks, keystrokes or inputs and usage statistics and are not sending data over the Internet in any way.
• Our extensions require user activation and can access webpage structures just to be able to make features available (for example listing embeded videos or page view to change it’s theme). The extensions do not collect any sensitive information (including passwords, phone numbers, credit card data) from webpages and do not process them in any way.
• We don’t ask you for personal information and we do not collect any system/computer data. We do not access your files, cookies or system information.
• We don’t share your personal information with anyone and we do not have any remote service that receives your stored or collected data.
• We don’t store your personal information or data on our servers in any way.

It needs the Web Page Contents permission to modify the colors on the webpage, and it could technically access creepy stuff like passwords, credit card numbers as a side effect, but the developer claims in very clear terms that it doesn't. I'm not sure what exactly Browsing History is necessary. You could contact the developer and ask him to explain the reason for the permissions in detail in the app's description or the privacy policy.

The fact that this is a popular app and the clear privacy policy make me think that there's nothing malicious going on here, it's just a technical requirement, necessary for the extension to alter websites' colors.

My understanding is that the extension can't be implemented without overreaching with permissions. I also have extensions that require the exact same permissions as seen on the screenshot you posted, AdGuard and a video player extension included with IINA. These extensions of course have no business viewing my passwords, but they need access to websites' DOM to do their work, that's why they're granted the Webpage Contents permission.

I think Safari simply doesn't allow for fine-grained permissions like running scripts inside Tampermonkey does. It's all or nothing in Safari, whereas in Tampermonkey you'd be able to see if a given script can communicate with the Internet, and to what website it sends data.