Or for measurements.
Referred here from the English SE: english.stackexchange.com/posts/365966
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They are Brackets, more specific Curly Brackets https://en.wikipedia.org/wiki/Bracket#Curly_brackets
But the usage of thoose as a measurements is wrong. Theese are the ones that could be used.
(But I am not sure what is the name in english, so probably someone can help) Dimension lines or something?
Probably a proper usage on a diagram could be this one: