Land Crawlers are Imperial agricultural vehicles and as the name suggests, are one of the vehicles 're-discovered' by Arkhan Land along with the Land Raider and Land Speeder. Land Crawlers are so successful and popular that untold billions of Land Crawlers are in service on almost every single agri-world across the Imperium thanks to their ease of maintenance and forgiving driving characteristics, with more than one historian believing it to be single most important find by Arkhan Land. Yeah, this glorified tractor is more important than the fucking Land Raider of all things, and it makes sense since a vehicle that can tend the feeding mouths of quadrillions of Imperial citizens is way more crucial to the survival of the Imperium than a giant Infantry Fighting Vehicle. Hell, though Space Marines can function without food for a very long time, even these guys need to eat sometimes.
Due to its ease of maintenance and Imperial laziness in designing a new combat vehicle, the Land Crawler has been pressed into military service on more than one occasion with variants such as the Bruennhilde, which served during the civil war on Krieg and is still used in some siege regiments.
Coming from the Germanic/Scandinavian Brunhilde which roughly translates to 'armor, protection + battle, fight respectively' and originates from Norse warrior queen Brunhilde the wife of Günther
The Bruennhilde is the Land Crawler's military cousin and its main function is to tow artillery vehicles much like the Trojan, Centaur and Atlas recovery vehicles. However like the Centaur, the Bruennhilde can also be used as a lightly armored transporter by PDF units of Krieg which has a track record for several millennia. Although it is armed with a single Heavy Stubber, the Bruennhilde is not a front-line combat vehicle, though it can be pressed into that role as needed.