Absolutely. But this is a separate question.

No, it's related. In programming, the only employment options are working for a government, for some corporation, or trying to sell directly to individuals?

Somebody who had worked for a recognizable tech company is far more hireable than somebody who is Self Employed or who has worked for the government.

But that's not prison labor. Prison labor specifically refers to penal labor. You receive no pay, because the labor is part of the punishment for the crime. It is the prisoner who is paying off his debt. In those cases, I don't think it is moral for private companies to make use of that labor for private gain. Penal labor should only be used for public benefit.

Here, we're talking about preparing someone for the job market when they leave. Hence, these are two separate concerns. You cannot substitute the former with the latter.

What is your ethical concern in this particular case. The remote work privileges seem to be setting him up for success after he leaves. The company he's working for doesn't seem to be unfairly exploiting his labor. This seems like a great success story for the Maine department of corrections. Who is being harmed here?

To me, it looks like a net benefit for the public, the department of corrections, and the inmate.

If you are worried about the inmate being allowed to build up savings that they can use when they are released, then that's on the judge. If the inmate has met their restitution obligations, then I don't have a problem with them being allowed to leave prison with savings that will enable them to get back on their feet again.