Testcase: {aaaaa overbrace bbbbb} underbrace {ccccc} the horizontal braces should stretch. This seems to be the same issue as bug 66024: the operators should have stretchy="true". See also the related bug 66279.
Although I can't see the little differences in this bug when comparing to your other bugs mentioned in the Description... But due the fact you are an expert and you know what you are doing -> NEW :)
Created attachment 81587 [details] testcase Here is the page currently generated for the testcase above. As you can see in Firefox, the braces do not strech whereas in LibreOffice they stretch to cover the "aaaaaa". This can be fixed either by using an explicit stretchy="true" (as in bug 66024 but for horizontal braces rather than accents) or by removing the explicit stretchy="false" (always generated as said in bug 66279). Well, it's true that the bugs are really similar/related and could have been grouped into a single one, but let's handle them separately.
Mass changes to assign bugs to myself.
Created attachment 81732 [details] New output I've submitted a patch for review: https://gerrit.libreoffice.org/#/c/4629/ I attach a HTML page with the new output.
Frederic Wang committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=e58d721709bd4e255f70cc824cd484cd1a1ec32d fdo#66281 - make underbrace/overbrace stretchy in MathML export The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Thanks :)!
Frederic Wang committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=477f5880039830885b12831ba2995e63953384aa fdo#66281 - followup: fix a comment for overbrace. The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.