Sleek door

block survival:door-sleek-windowed-aged · from game

Can be generated by (1)

Random-stack placeholders (placed in world-generated chests and similar) whose pool includes this. The chance is among that placeholder's results, not the chance of finding it.

Placeholder	Chance
Lantern randomizer	9.93%

Found in structures (11)

Structure	Kind
Trader camps built on large trees	structure
Large trader outposts	structure
Village area	storystructure
mansion	storystructure
sunrift	storystructure
thepanopticon	storystructure
megastructures-oasis-stadrian	structure
megastructures-settlementofkeykeepers-sirayne	structure
largeruins-0207-samgrey-o7	structure
desertspecifc-o20-stadrian-undergroundwithentrance	structure
desertspecifc-wildwest1-virrno-o4	structure

This confirms the schematic(s) contain this code somewhere, not where or how many times -- the per-instance block-entity decoding used for tapestries isn't run for every content type.