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.
Environment
Windows 10 64-bit, Java 8u91 (using the minecraft launcher java version)
MC-102135
Structure block: Empty names allowed
Resolved
Fixed
0
Confirmed for
16w20a
It is however not missing a quotation mark because these are two single quotation marks