Source trace of owned-check.c. Not a program run.

Rule visible in desk_code:
length_of(text) is compared with 4.
Equal: return 1.
Otherwise: return 0.
A text pointer that is 0 makes length_of return -1, which is not 4, so desk_code returns 0.
The end of a text value in this source is the '\0' marker. The count stops before that marker.

Worked input "desk":
Characters d, e, s, k, then the end marker.
Count is 4.
4 equals 4, so the source returns 1.
Predicted from the source. Not observed.

Activity input "notes":
Characters n, o, t, e, s, then the end marker.
Count is 5.
5 equals 4 is false, so the source returns 0.
Predicted from the source. Not observed.

A matched run would be confirmation. No binary was built, so nothing was confirmed by execution.