I just realized that when I post this link with the intention to have it oneboxed:
it is rendered as an ordinary link because the website obviously doesn’t support OpenGraph. In cases where that happens, I tend to change the text so that the link becomes an inline link. And in that case it renders as a mini-onebox: https://cispe.cloud/publicregister/ Nice!
So I’m wondering: wouldn’t it make sense if the ordinary onebox would fall back on mini-onebox whenever no meta-data is available?
I am not sure this is relevant because mini one box is only supported for internal links by default in this release.
There is a very very easy workaround here, just add a space prior to the link.
It should probably fallback if you have mini onebox enabled on all sites, and we may move to mini onebox enabled on all sites in a future release.
There is an element of risk cause some sites may have real bad metadata.
For what is worth, I noted this behavior by coincidence and I wasn’t sure about what was going on - see OneBox doesn't render boxes for Phabricator URLs.
The space trick is simple and very useful… once you know it. I had noted that (some? all?) external URLs show the page title when placed in the middle of a paragraph, but I hadn’t made an association to exploiting this feature as standalone link with an extra space.