It depends a lot on the model - if you let us know what range you're looking in then people can tell you what the model numbers mean.
Currently, Kubota numbers are generally one or two letters that tells you the frame size, two digits of HP, two digits of series. With, of course, some exceptions to make things harder for people trying to follow along at home.
So, B2601. B-series chassis. 26HP (or thereabouts, the numbers are approximate). 01 series (so often called B01 for short).
L3302. L-series chassis. 33HP. 02 series, which has some enhancements over the L01 series (mainly brakes on the left, electronic clutch on the PTO, and floor mats).
However, in the older series, there were some tricks. So in the 2010s, there were two B sizes - the B01 and the B50. A B2650 was a 26HP machine, but had a bigger frame than a B2601. The B50 series got renamed to the LX series recently, fixing that anomaly.
Going back to the 90s, the numbering was very different. A B7100 was not a 71HP machine, for example, it was pretty much the same size as the current B2601, or the older B2650. So then you're into just knowing what individual models were - the numbering isn't directly telling you useful information.
The other renaming relatively recently was the loader numbers. The loader number now roughly tells you the lift capacity in kg. So a B2601 with an LA434 loader will lift 430kg at the pins. Older loaders this wasn't the case.
The engine models also tell you something. A b2601 has a D1105, which is a 3 cylinder (from the German apparently, D something means 3 cylinder), 1.1 litres. 05 is the series, all the 05 series have similar technology. The L4701 has a V2403. The V means 4 cylinder (again German), 2.4 litre, 03 series is older tech than 05 series.
