Closely relates to MC-54988, and likely also MC-241321.

The bug

The redness effect which can be seen around the edges of the screen when near the world border will be hidden if the player presses F1.

Whether or not this is intended is unclear, as many other tickets in this vein have been either fixed or considered intentional; input from Mojang is needed on this matter. The following list is of tickets involving similar effects that disappear(ed) with F1 and their resolutions:

• MC-73730: darkness vignette - awaiting triage/resolution
• MC-196469: nausea green tint - was fixed
• MC-83353: nether portal overlay - considered intentional
• MC-121536: carved pumpkin overlay - considered intentional
• MC-203575: spyglass overlay - considered intentional
• MC-205029: powder snow overlay - considered intentional

How to reproduce

1. Get close to, or past, the world border
2. Press F1
   1. Note that the red haze at the corners of the screen disappears

Expected results

Pressing F1 would have no bearing on this red vignette effect - it has extreme similarity to the nausea haze.

Actual results

F1 shows or hides this effect.