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Also, they say it does timeboxing, but it's not evident they understand the notion of prioritization through pre scheduled and empty timeboxes, that tasks fill by category match, then do not overfill but spill to the next available timebox of that same category, allowing you to meta-manage your prioritization by category of task vs. amount of recurring timeboxes as a proportion of your week, rather than by task.
EDIT/ADD:
Upon review of the user manual, they seem to think "timeboxing" is the alternative to "playlisting", meaning, do you book actual time on your calendar for a task, versus, do you burn through a list of tasks when you are in task mode.
They seem to miss that timeboxing is the opposite of calendaring particular tasks, it's a third way.
If you have calendaring tasks, and playlisting tasks, timeboxing is calendaring big chunky timeboxes (not tasks) for "headspace" around sets of tasks, then playlisting the matching subset of tasks within that timebox.
There seems to be a concept of channels (#hashtags) and an ability to auto-schedule within channels, and an ability to have per channel schedules. Depending how implemented, that combination of features might allow actual timeboxing, which, incidentally, could line up well with the legitimate timeboxing offered by SavvyCal, my favorite "meet with me at a time that works for you (and me)" tool.
You should not, ever, be "dragging a task to the calendar" in timeboxing. The task should be in a class that you have a timebox for (their channels notion) and if you have unclassified tasks, you can playlist them in a "random tasks" designated timebox. To force a task to be in the next available timebox for that class, you prioritize the playlist.
Unfortunately, as someone was curious about, this doesn't support Linear, though perhaps you could do it transitively through, say, GitHub.