The Chromium project decided that the EXT family of filesystems are surplus to requirements, but has bowed to pressure and signalled it is willing to reverse the decision.
As detailed in this thread, the project's developers feel that as Chromium is intended for consumer devices, the ability to read external media formatted with the EXT 2, EXT 3 and EXT 4 filesystems is not a feature it is felt necessary to maintain in future versions of Chrome OS.
The reasons for the omission are that the EXT family is not widely used, so support is considered a “minor” and dispensable feature.
EXT 4 is included in the Linux kernel and the EXT family of filesystems was created specifically for Linux. A question comment from user “oneofone” to the effect that “Is this some kind of a joke? you're basing your OS on Linux yet removing support for Linux filesystems?” therefore looks apt.
Other participants in the thread worry if Google – like many before it – is not paying enough attention to the Linux community, or not paying its dues – karmic or otherwise – to Linux.
The decision to bin EXT was considered months ago and finalised in September. Anger became apparent in recent days, to the extent that a few hours ago developers at the project have signalled an intention to reverse the decision. " I'm confident we can improve the situation," wrote one, although there are no guarantees the change will be enacted. ®