It is something similar to the current Go to Match Brace feature, but it is not call when cursor at one of the matching brace, but in the middle of the two, so it has two direction, beginning & ending.
Here is demo
1:{
2:{ Cursor B
3:[
Cursor A
~3: ]
~2: } Cursor C
~1: }
1. say I am at Cursor A, inside of 3 paired braces, when I call beginning, I go to 3:[, if I call for ending, I go to ~3:]
2. similar, when I am at C, the beginning is 1:{, ending is ~1: }
this give us easy to know the scope of a given line, not finding the braces by my own eyes.