is attack on titan (shingeki no kyojin) episode 60 filler?

It is the year 854, and Marley has been at war with the Mid-East Allied Forces for four years, and as a result, has been forced to put its mission to retrieve the Founding Titan from Paradis Island on hold. The Marley fighting force consists mostly of Eldians under the command of Marleyan officers.

To finally win the war, Marley's forces intend to capture Fort Slava, which will allow them to invade the port where the Mid-East Allied Forces' fleet is currently residing, and destroy it.