You can enter nothing as the name for a structure before saving it, resulting in displaying
Structure saved as "
in chat, with one missing pair of quotes.
MC-102135
Structure block: Empty names allowed
Resolved
Fixed
2
Confirmed
Minecraft 16w20a, Minecraft 16w21b
Minecraft 1.10 Pre-Release 1
Retrieved
Confirmed for
16w20a
It is however not missing a quotation mark because these are two single quotation marks