MC-133425Missing Glyphs for '［' (U+FF3B) and '（' (U+FF08)
They appear in Japanese translation for "key.spectatorOutlines", "command.context.here", and so on.
A partial list of characters that could be displayed in 1.12.2 but not in 1.13:
（［｛｜￤
(U+FF08, U+FF3B, U+FF5B, U+FF5C, U+FFE4)
2018-07-13, 05:24 PM
2018-07-31, 08:45 PM
2018-07-26, 10:54 PM
33
12
Minecraft 1.13-pre8, Minecraft 1.13-pre9, Minecraft 1.13-pre10, Minecraft 1.13