Back when Border Crossing was released for our favorite game the longfellow's textures was accidently updated to feature this blue variant instead. According to the games files this is known as "fps_vehicle_muscle_2" indicating this would've been either a variant of the pre-existing Longfellow or Starbreeze wanted to do customization with it just like how the escape van can be customized. After Border Crossing, another patch was released which this texture for this was scrubbed out of the games files and removed permanently. This mod simply adds back that texture and replaces the default Longfellow.
Also something i've noticed while looking at the patchnotes, OVERKILL_Tobias commented "Seems like Hoxton got himself a flat tire." just before the patchnotes, i'm betting this is something related to them removing the texture because they accidently shipped a feature they didn't want in the game to begin with, or this could be something completely unrelated.