It means "this assert should always fail, but I wanted to embed some information in the failing assertion message". Example without and with the && string:

```
Workpad% cc crash.c
Workpad% ./a.out
Assertion failed: (false), function main, file crash.c, line 8.
zsh: abort      ./a.out
Workpad% vi crash.c 
Workpad% cc crash.c 
Workpad% ./a.out
Assertion failed: (false && "we done wrong"), function main, file crash.c, line 8.
zsh: abort      ./a.out
```