Difference betwen two rear derailleur? What is the difference between these two rear derailleurs?

On the pictures it seems, that the "rotation angle" is different.



https://bike.shimano.com/en-EU/product/component/tourney.html

On the item descriptions, all details are absolutelythe same.
If the specs are identical, then they are functionally the same. There is no 'rotation angle' spec - the body of the derailleur rotates around the 'B pivot' and these two just happen to have been at slightly different positions when they were photographed.

The product names suggest the FT55 is slightly better than the FT35, but I don't think there is really any difference in quality between components in Shimano's Tourney range.