uchg
uchg is a user-immutable file flag used in BSD-derived operating systems, including macOS. It is one of several file flags that can be set or cleared with the chflags system call. The flag indicates that the file is immutable from the perspective of ordinary users.
When the uchg flag is set on a file, its contents and most metadata cannot be modified,
Setting and clearing the flag is done with the chflags command. To set the flag on a
Viewing the current flags can be done with a long listing that shows file flags, for example
Related concepts include the system-immutable flag schg, which is a stronger protection at the system level.