What does 1.0 It current mean?
The datasheet has a 'Glossary of Terminology' which includes the definition of lt.


  Represents "Current" and is defined as follows It(A)= Rated Capacity (Ah) / 1(h).


As such, it appears to be the same as C rating ( i.e. 0.7lt charge current is 0.7C charge rate - after one hour, charge will be 0.7 times capacity in amp hours)

(the pdf seems to use lowercase L lt and uppercase i It inconsistently)