[tomrod]

> legal redlining

Is this underlining, and not redlining as defined in financial services? (redlining: differential pricing based on demographic makeup of a zip code or neighborhood)

[URSpider94]

Attorneys and business folks use it to mean “marked up” - a redlined contract has additions in red, and removals in red with red lines through them.

[prdonahue]

Redline as in how strikethrough appears in Word. It's a colloquial term.

[h4b4n3r0]

OP was referring to diffing changes between the original and modified version of a legal document (typically a contract).