Configuration

config/culltag.properties is written on first start and rewritten every time it is read, so a key you delete comes back with its default and an unparseable value is replaced with one. Edits take effect on /culltag reload or a restart.

Key	Default	Range	What it does
enabled	true		Master switch. Turning it off restores every nametag immediately rather than just stopping the sweep.
max_distance	32	1 to 64	How far apart two things can be and still be checked. Beyond this they are left exactly as vanilla draws them.
check_interval_ticks	10	1 to 40	Server ticks between sweeps. 10 is about twice a second; 4 is about five times a second.
cull_entity_nametags	true		Also cull named mobs and armour stands, not just players.

Notes on each:

• max_distance is the main performance dial, because it decides how many things get a ray. It is capped at 64 because vanilla stops drawing nametags at 64 blocks, so checking further can never change what anybody sees.
• check_interval_ticks is a latency dial, not an accuracy one. At 10 a player stepping out of cover can keep a hidden nametag for up to half a second. Lower it if that half second matters in PvP; the cost scales linearly.
• cull_entity_nametags covers named mobs and named armour stands, which vanilla draws through walls exactly as it draws a player's. Invisible entities are always skipped, whatever this is set to, so armour stands used as holograms stay readable through terrain. Turn it off if you have a large number of named visible mobs in one place and want the sweep cheaper.

Which blocks hide a nametag is not in this file. It is the #culltag:transparent block tag, which ships covering glass and stained glass, every glass pane, iron bars, chains, ladders and scaffolding. Anything in that tag is seen straight through; anything else with a collision shape blocks. Override it with a datapack the same way you would any vanilla tag:

// data/yourpack/tags/block/... is not it; override CullTag's own tag instead:
// data/culltag/tags/block/transparent.json
{ "replace": false, "values": ["minecraft:oak_leaves"] }

enabled is also written back to the file by /culltag enable and /culltag disable, so a toggle made in game survives a restart.