Mozilla.org has released the long-awaited "alpha" version of its open source Web browser, dubbed M13, in a signal that the troubled project may finally be putting some of its problems behind it.

With the alpha, which is posted on Mozilla_ Web site, the organization is expressing its confidence that the software is stable enough to be a user_s primary browser and mail client, although it still will go through several versions before a final release. In general, an alpha version is not considered stable enough for the public, but Mozilla watchers may want to give it a test spin. Neither Mozilla nor Netscape could be reached immediately for comment. The release is a major milestone for Mozilla, which was founded by Netscape Communications to handle the open source development of the Communicator browser. During its short history, the group has struggled to meet deadlines and has suffered several key employee defections.