Why is L1 written using angular brackets while the definition of L2 uses square brackets? Why do we add S to L1 if it is already there?

How do we interpret S in T1? I thought that since this is the only non-logical symbol in the alphabet, it is interpreted by the single relation <. However, T2 uses <, which is not in the alphabet, instead of S.

It seems that T2 is consistent: just interpret c1 = c2 = c3 as 1 and e as 2.