The bug

The world border cannot be set to any value beyond 30 million.

This was strongly implied to be a possibility due to MC-187668 being resolved as a duplicate of MC-187664, which was later fixed in 21w17a. Despite said fixing, this remains an impossibility: while access beyond this point was heavily implied by these actions (making this probably not a feature request), it is not possible.

How to reproduce

1. Visit the world border
2. Attempt to set the world border beyond its default 60 million block diameter
   1. The world border is clamped to a maximum value of just under 60 million, rendering this an impossibility
3. Now change the center of the world border such that it would also be expected to include terrain beyond 30 million blocks
   1. This fails as well, resulting in a rectangular border and forbidding any further traversability

Expected behaviour

Due to the reasons detailed in the introductory paragraph, the terrain beyond the 30 million mark would be accessible via changing the world border.

Actual result

Anywhere beyond this region is still completely off-limits despite the given reasoning.

How to fix

Section upcoming...