Full Idea
Another style of proof often cited as unexplanatory are brute-force methods such as proof by cases (or proof by exhaustion).
Gist of Idea
Proof by cases (by 'exhaustion') is said to be unexplanatory
Source
Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.1)
Book Reference
Colyvan,Mark: 'An Introduction to the Philosophy of Mathematics' [CUP 2012], p.80