Our mounted knight fights with the best protection that is available for our period, and full mail hose (known as chausses) are worn. These are a development of an earlier form that just protected the front of the leg, being tied with long laces all the way up the back. These full mail chausses are heavy items, and the nature of mail means that they need a lot of support. To that end, they tie off to a stout belt which rests on the roll at the top of the braies: this is adequate enough to take the weight of the thigh armour. The knee needs to flex, however, so further tight ties around the leg below the knee support the mail on the calfs and also provide a small "bag" of mail for movement at the knee.
These chausses also cover the feet. To be able to put them on over the heel, there is an amount of mail that can't tightly follow the skin at the ankle. Again, the illuminations never show this on armoured men, but fortunately spurs help to hold the mail together at this point. Possibly this is another illustrative short cut, but it might also suggest that mail is slit and has a short lacing behind or beside the inner ankle.
Similarly we don't know what happens below the foot - it is unlikely that a mail sole was used - so adopting what occurs on the palms of the hauberk makes sense and as a result the mail at the edge of the foot was possibly stitched to a leather sole.
The chausses I've made weigh about 6 kilogrammes each and, like some pictured examples, don't have these integral feet. Once tied on firmly (and this is essential in order to ensure that the mail moves with the leg) they are relatively unnoticeable. They limit leg flexibility only a little bit - certainly not enough to prevent me running up or down steps, for example.