'open' (item from an unidentified developer) has appeared in my login items. Does anyone know what this might be/where it is from? Thank you

Best to just ignore the Background Apps panel in System Settings as it is currently broken or improperly implemented. Apple has not even provided their developer community with any details about how their apps should work with this "new" feature. Right now third party apps can appear or show in multiple ways.

FYI, This is a known issue regarding the new macOS Ventura System Settings for Background Apps configuration. @etresoft (an Apple developer of third party apps) talked about this "Background Apps" System Settings panel in another private thread. Seems like bringing this feature out to the user was not done well and Apple never provided any information to the developers about how to have their apps handle this new "feature" setting. Best to just ignore the Background Apps System Settings panel alone for now until Apple straightens things out with the feature and developer information.

The "open" is a lower level command line utility used to launch GUI based apps from the command line (perhaps can do more than GUI apps, but that is all I've ever used it for myself). Due to the improperly implement Background Apps feature in System Settings it is bringing up this utility without providing more information (@etresoft discussed why it does not have this information in the other thread).

If you do anything to attempt to "fix" it, you will likely break the app. Best to ignore anything in the Background Apps System Settings for now.

If you click on that small i with a circle around it, it will let you go to it's location which might help you identify it better.

If the location is pointing to a .plist file, you can open it with TextEdit to see more details about it. I can't confirm one way or the other if it's from Apple. However, since you have it disabled, there's not much to worry about.

The only explanation is that it is just a poorly implemented feature on Apple's part. That ⓘ button is useless because it points back to Apple's own "open" tool. This probably is an "identified developer" that the "open" tool is opening.

I'm afraid Apple is just phoning it in these days. Even to add that ⓘ button above required me to navigate two different Apple bugs/annoyances in order to add it to my reply.

Third time is a charm as they say. "open" was added to login items today on my M1 MacBook Air which was idle at the time. The creation & modified date is Feb 9, 2023. I'm leaving it active.

Coincidentally, my Time Machine drive brought up a disk ejected improperly message despite no evidence it actually was ejected.

It's a mystery. 😎

I've had exactly the same happen today and would like to better understand what this relates to.

dialabrain wrote:

It's a mystery. 😎

Interestingly enough, "open" has not been added to my iMac Pro, also running Ventura 13.2.1.