The YebF-like protein family appears to be a group of colicin immunity proteins. As well as YebF the family includes cmi, the colicin M immunity protein. This domain family is found in bacteria, and is approximately 80 amino acids in length. The alignment contains two conserved cysteine residues that form a disulphide bond in the solved structure.
Jiyao W et al.(2023). "The conserved domain database in 2023.",