We don’t have enough details about this change but the latest Chrome OS Beta channel is now available. Specifically, this is the 67.0.3396.41 beta. Some users have reported to be receiving the update and shared that Android apps can now access the SD card. As with most builds, this one delivers feature enhancements, security updates, and a bunch of bug fixes. The Chrome Releases blog has listed several changes like removing Chrome Home logic in location bar that causes a crash, disabling iTunes URL handling feature by default, instrument variations seed loading in WebView, and fixing NPE on x86 devices.
How do we know Chrome OS can now access an SD card? The Storage settings show the available ‘Portable storage’ aside from the ‘Internal shared storage’ and the ‘Total used’ of the Device storage. This change could possibly be used in coding and developing apps on Chromebooks in the future. It may also have something to do with the Alt OS to dual-boot Chrome OS and Windows.
It’s no secret that Chrome OS can also run Android apps but we have yet to see and experience the full features. There are only a few Chromebook models that could do such so note that there are still certain limits.