If I had to hire a progammer for a job, the first things I would ask any applier are:
You do not actually have to be a programmer in order to ask the questions above. You do not have to look at the code. But you should try to see if the applicant is nervous about certain points or if the community responses are rather bad.
Additionally, the employer has to check all the things they would ask for any other position. They have to check if the person can integrate into the existing team, if they are diligent, why they want to have that job position, why they want to join the company, what they do in their free time (are they social or might they show problems later on?),...