Visible Invisible

Instead of removing the invisibility potion effect, the mod applies a glowing outline to invisible mobs and players inside the player's line of sight. The outline uses the same look as the Spectral Arrow effect, so the rest of the game keeps its standard visual style and tracking movement stays clear. Outlines only appear on invisible entities within the field of view, and the mod is aimed at spotting them against the background.

The outline is a toggle bound to the V key. Pressing it switches glowing detection off at once, which allows a quick change between standard vanilla play and the enhanced detection mode. The mod is built as a visual aid, somewhat like an X-ray view limited to invisible targets, and it only needs one keystroke to operate.

Visible Invisible is client-side only, so only the player who installs it sees the outlines and no server changes are needed. It is published for Fabric only, for Minecraft 1.21.11, and is released under the MIT License, so the source code is open source. Its code is built for high performance, and the author describes it as having no measurable impact on frame rate.