Two days after Microsoft released Windows 10 Insider Preview build 20241 to the Dev channel, it's releasing a cumulative update. The new build number is 20241.1005, and according to Microsoft, it's sole reason for existence is to test the servicing pipelines. According to the blog post, there are no fixes.
This is the third cumulative update in the Dev channel in less than two weeks, and all of them have been simply to test the servicing pipeline. This is a normal practice, of course, because Microsoft does have to be able to service its updates. It doesn't seem like something that would be quite as necessary in the Dev channel, being that the Dev channel is strictly for the rs_prerelease branch.
Of course, this could also mean that the firm is prepping a version for the Beta channel. While the Dev channel isn't tied to a specific release, the Beta channel is. Being that the Windows 10 October 2020 Update, or version 20H2, was released earlier this week, something new should be coming to the Beta channel soon.
It's unclear what's coming though, because there have been rumors that 21H1 has been canceled in favor of the Windows 10X RTM, something that was originally supposed to happen alongside 20H2 before there were delays. It's also possible that there might still be a 21H1 update, although it could be more similar to the enablement package strategy that we've seen from 20H2 and 19H2. we should find out soon.