Apparently that's a thing.

Deflate64, specified by PKWARE, is a proprietary variant of Deflate. It's fundamentally the same algorithm. What has changed is the increase in dictionary size from 32 KB to 64 KB, an extension of the distance codes to 16 bits so that they may address a range of 64 KB, and the length code, which is extended to 16 bits so that it may define lengths of three to 65,538 bytes.[4] This leads to Deflate64 having a longer compression time, and potentially a slightly higher compression ratio, than Deflate.[5] Several free and/or open source projects support Deflate64, such as 7-Zip,[6] while others, such as zlib, do not, as a result of the proprietary nature of the procedure[7] and the very modest performance increase over Deflate.[8]

https://en.wikipedia.org/wiki/DEFLATE#Deflate64/Enhanced_Deflate

Probably not very prevalent of a format out there, though.