This build adds a new Export Manager. This basically lists your last few exports so you can access them again, in case you forgot to download the file or otherwise lost it. The main reason it exists though is so you can add your own exported zip and build it with Scirra's mobile app build service. This will ultimately allow a Construct 2 Cordova export to be built to an APK in Construct 3. There's still a bit of work to be done though, including updating Construct 2 as well, but the Export Manager is still there for you to try out in the mean time.
Secondly in this build we've done a lot of work to update the effects engine, which renders WebGL shader effects. There have been some long-standing issues with effects which we're working on fixing for Construct 3. In particular some effects such as Warp were inconsistent with scroll, zoom and the viewport edges. Several effects have been updated to work better in these aspects, and in the case of Warp we've actually replaced it with some new revised effects. The new effect's parameters work slightly differently, so to ensure existing games don't suddenly look different, we've introduced new effects and deprecated the old Warp effects. Assuming these changes go smoothly, we'll be able to add support for effects in the Construct 3 addon SDK soon after this. We had to make some significant changes, and we don't want to unnecessarily burden third-party developers with breaking changes, which is why we've been holding off on that.
Finally as ever there is a batch of bug fixes to help ensure Construct 3 is robust. We did make one breaking change this build, regarding how the Platform behavior's Is by wall condition works. Previously it was false if the player was next to a wall but directly underneath the ceiling. This seemed somewhat counterintuitive so we've updated it to return true in that case. Technically this is a breaking change since it changes how an existing feature works, but it does seem like it ought to have worked like this anyway, so hopefully it is not a significant inconvenience.