What is a sector-based level editor?

In the old days, text files were talking about line-based and sector-based map editors. An example of line-based would be even Doom Builder, according to the wiki. How does sector-based differentiate from that? Wiki says DoomEd by Geoff Allan may be like that.

I tend to think of WadAuthor as sector-based because it simply doesn't have a function to draw lines. You just drop in a new sector and stretch it around to fit, splitting linedefs as needed. Never used DoomEd, so unsure how it compares.