CTAN update: l3backend

[CTAN Announcements]

The LaTeX Team submitted an update to the

                l3backend

package.

Version number: 2021-03-18
License type: lppl1.3c

Summary description: LaTeX3 backend drivers

Announcement text:
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## [2021-03-18]

### Fixed
- Maintain stack color correctly with `(x)dvipdfmx`


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This package is located at 
   http://mirror.ctan.org/macros/latex/contrib/l3backend

More information is at
   https://www.ctan.org/pkg/l3backend

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   Thanks for the upload.

     For the CTAN Team
    Erik Braun

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