Here's the variable in context:
This Fontwork dialog is only available for Fontwork in old Writer text documents that were created prior to LibreOffice %PRODUCTVERSION.
The variable should either be evaluated to a number, or (probably better) replaced with a static value.
It is not appropriate to use %PRODUCTNAME %PRODUCTVERSION here. Clearly, it refers to a specific version, which should not be a variable. For the git log I found out that presumably author was referring to OpenOffice.org 2.0.
Andras Timar committed a patch related to this issue.
It has been pushed to "master":
fdo#62291 use OpenOffice.org 2.0 instead of %PRODUCTNAME %PRODUCTVERSION
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:
Affected users are encouraged to test the fix and report feedback.