There is currently a shortcut to mark ALL timelines as read (ctrl-R by default). It would be very handy to be able to mark the currently viewed timeline as read. Equivalent to the little button that appears above the scrollbar in the top right.
Choqok is unfortunately no longer maintained. If a new maintainer wants to step up and take care, the project is archived here: https://invent.kde.org/network/choqok You can just clone it in your private namespace on invent.kde.org and if you have started to work on it and fixed/implemented something get it reviewed and the project unarchived. Sorry for the inconveniences.