Comment 4 for bug 1905188

No PowerPC image was released for Lubuntu in recent 16.04 point releases. The URL it points to suggests that there had been a powerpc image released as part of the initial 16.04 GA release, but none thereafter. (I can't easily check the history to confirm that it was released as part of 16.04.0.)

Regardless, as part of the subsequent point releases, this image was removed from the server and archived, so if the Lubuntu community haven't separately downloaded it and published it somewhere for consumption, it is non-trivial to put it back online. Also, the fact that no point release updates for this image were made indicates the Lubuntu community does not actually support powerpc (and 16.04 was released 5 years ago, and there is officially no security support for powerpc).

So I have resolved this bug by removing the dead download link.