Running the game in widescreen resolutions makes the block selection outline become thicker.
MC-229753
Block Selection Outline becomes thicker with widescreen resolutions
Open
2
(Unassigned)
Confirmed
(Unassigned)
1.17, 1.17.1 Pre-release 1, 1.17.1, 21w41a, 1.20.6, 24w18a
Retrieved
Can confirm in 23w51b. This behavior also applies to any lines rendered via shaders, such as entity hitboxes (F3 + B), or chunk borders (F3 + G).