I don't think that's added by mistake. While it's a different spec, HTML also uses "run" as a noun meaning like a sequence.
(And that confuses people, too. whatwg/html#6782)

Yeah, a text run is the thing in the box tree that represents a sequence of adjacent DOM text nodes in the element tree. Basically:

• The DOM tree contains element nodes, text nodes, comment nodes, doctype nodes, etc.
• The element tree contains elements, pseudo-elements, and text nodes.
• The box tree contains boxes (representing elements or pseudo-elements) and text runs (representing sequences of text nodes).

Re-opening in response to @myakura's comment, because maybe we should rename “text run” to “text sequence”!

"text run" is a term used elsewhere for similar purposes, e.g. https://learn.microsoft.com/en-us/dotnet/api/system.windows.media.textformatting.textrun?view=windowsdesktop-7.0 That said, I'm not sure if the use in the display spec matches the meaning in Gecko (where it has been used for a long time).

@dbaron They're similar but not quite the same. IIRC text runs in Gecko can cross element boundaries, as long as there's no styling change that would create an interruption. Either way, though, I think it's worth using terminology that's less likely to confuse people.

I think “text run” is a term of art that does not quite match what is being described in the spec, and I don’t see a benefit in using that term that offsets the confusion being generated. So I support changing to “text sequence.”

Since this change is fairly low-impact we likely do not need to spend meeting time on it.

The CSSWG will automatically accept this resolution one week from now if no objections are raised here. Anyone can add an emoji to this comment to express support. If you do not support this resolution, please add a new comment.

Proposed Resolution: Change the term “text run” to “text sequence” in css-display-3

RESOLVED: Change the term “text run” to “text sequence” in css-display-3

There are other specs that use "text run" as well. I see Text and Writing Modes use it. Does the resolution cover other specs?
https://drafts.csswg.org/css-text-4/#valdef-word-boundary-detection-normal
https://drafts.csswg.org/css-writing-modes-4/#text-combine-runs

We would definitely need to change css-text since it links to the css-display definition. I think we should also change css-writing-modes for consistency.

Yes, we would apply the change across all the CSS specs that reference the same concept.

@letochagone Ok, I've updated the editor's draft in e0f9cb9 to use the word “text sequence”; hopefully this will be less confusing. :) Let me know what you think.

@myakura I also updated all of the other specs that seemed to be referencing the same concept. There remain some uses of “text run” in Writing Modes, Text, and Fonts which don't seem to be quite tied to the same box tree concept, so I left those alone. Feel free to file a follow-up issue if you think something is off. CC @svgeesus

@fantasai Why do flex and grid use different wordings now?

and each contiguous sequence of child text sequences

and each child text sequence

I think the latter is better, "sequence of sequences" seems unnecessarily verbose.

@Loirooriol Fixed, thanks.

I think the latter is better, "sequence of sequences" seems unnecessarily verbose.

But doesn't it affect the meaning? Will "each child text sequence" not imply that each text sequence created by a display:contents child becomes a separate flex/grid item? I believe that "sequence of sequences" wording was specifically introduced to clarify that they will become a single flex/grid item (possibly with differently styled parts of text), though I agree that there should be better wording to express this intent.

Good point, I didn't consider display: contents.