Update from February 2024: I have uploaded a version 2 which is easier to print and still has a handle to pull.

This is a clip for my composter (sold in Germany), used to hold the four walls together. I've remodelled the original clip (green at the pictures), but haven't printed it as it needs quite a lot of support structures. So I can't tell if it fits, but it should.
I've modelled a second variant (grey at the pictures), which is much easier to print and needs a minimal amount of support structures. It's a little bit tighter and smaller than the original (= uses less material), fits perfectly on my composter, and it should be strong enough for long term usage.

PS.: I noticed that the pull handle breaks quite easily if the part is printed in the same orientation as in the pictures. Mine broke between two layers - so print differently or handle with care.

Notes:

I recommend printing it in PETG or any other material that is UV resistant and provides a bit of flex (more flex than PLA).
I've used tree supports and only supported anything above 85° (= so only the handle).
Furthermore, I had a bit of bed adhesion problems and thus used a brim of 5 lines.