The Chrome OS Dev Channel has a new Chrome 69 build now available. The new build is the fourth Chrome 69-based build to land in what is considered the “alpha” testing channel. 69.0.3494.0 (Platform version: 10888.0.0) is the new build that you are looking for and it is available for the majority of devices in the channel now.
As you would expect for a build at this early stage, there are a lot of bug fixes and tweaks in this update according to the release notes. Doing a quick dive into them, I did not find any new features mentioned. This looks like a prep build to get it ready to go to Beta testing in the Chrome OS Beta Channel.