That's not an official repo, it's what someone pulled out of the GPL code that EA has posted. the EASTL is much larger and some parts have been changed. Perhaps someday the EASTL will see the light of day in a full, supported form :-)
To be strict EASTL is not an "implementation of" the STL, it's a "replacement for". It has similar functionality (containers, algorithms) but the API is not compatible. In particular, EASTL has different memory management that is more suitable for games and especially consoles.
I used to maintain EASTL. I think it's more accurate to describe it as an implementation of the STL than a replacement. As far as possible it is API compatible with the STL, the API differences are primarily in the allocator model and it is possible to write EASTL code that compiles against another STL implementation with fairly minimal changes, almost none if you're not using custom allocators. There are a few extensions / extra containers but we went to great lengths to keep as much of the API identical as possible.