Use embedded content processing in the Excel file type.

Enter \[.+?\] as placeholder:

Thanks for taking the time to answer, Jerzy, and thanks for your suggestion. It's a step in the right direction. :)

The text in square brackets now appears as a tag and is not counted as translateable. But the file isn't segmented at the tags. Instead, the tags still appear within the segments:

Translate, translate, translate.[Tag]Translate, translate.[Tag]Translate.

Do you have a suggestion how to make Studio segment the text so that each tag is a segment of its own?

Translate, translate, translate.

[Tag]

Translate, translate.

[Tag]

Translate.

(It doesn't have to be tags, I'd be fine with the text appearing as normal text, even as translateable text. I just need the segmentation like this.)

You need to edit the advanced settings of the Inline Rule described by Jerzy. There you need to enable "Is Word Stop", so that a punctuation mark directly in front of the tag in question is correctly recognized as segmentation boundary.
Unfortunately the setting "Inline Tag Behaviour: Exclude" does not work for the Excel filter, but only for the RegEx Text filter.

ok - so why not forget the tag rule and just use segmentation rules.  If you add two rules (the easiest way) it'll give you exactly what you want:

To do this I added two new rules:

First rule

Before break

\[.+?\]

No after break.

Second rule

Before break

\w\.

After break

\[

That's it.

sjohansson said:

If you set the filter settings to "All Content", you'll be able to see these tags as well.

The advantage of this of course is the bits you don't want won't count towards the analysis and you won't even have to handle them.