I see today that the Kokua Viewer, the successor to Imprudence Viewer, has been added to the Second Life Third Party Viewer (TPV) Directory. You’ll find it listed in the second section of the list. The Kokua wiki page is here: Kokua Viewer.
The second section of the directory is for viewers that do not report crashes or do not have enough users to report a significant number of reports. So, it may move to the first section when enough reports are collected.
They also have a development viewer: Kokua Viewer 3.5.2.