[NTG-context] What does #+ do?

Hi list! In evenmore pp. 76-77, concerning LMTX extended macro parsing, the following examples of #0, #+ and #- are given \def\TestA#1#2#3{{(#1)(#2)(#3)}} \def\TestB#1#0#3{(#1)(#2)(#3)} \def\TestC#1#+#3{(#1)(#2)(#3)} \def\TestD#1#-#2{(#1)(#2)} So \TestA1{\red 2}3 \TestB1{\red 2}3 \TestC1{\red 2}3 \TestD1{\red 2}3 give (1)(2)(3) % red from "2" onward (1)()(3) (1)(2)(3) % only "2" is colored (1)(3) What I guess is that #+ pass an argument, grouping braces included (the report says an argument is passed "as-is"). I see it as really useful. But, apart from the example above, are there any other differences between doing, say, \def\foo#1#2#3 and \def\foo#+#+#+{#1#2#3}? Thank you very much. Cordially, Jairo :)