dcl-margin-label-offset

dcl-margin-label-offset is a variable defined in `dcl-mode.el'.
Its value is

2

Documentation:
Number of columns to indent a margin label in DCL.
A margin label is a label that doesn't begin or end a block, i.e. it
doesn't match dcl-block-begin-regexp or dcl-block-end-regexp.

You can customize this variable.