In Calc press Ctrl+H, enter something to "Search for" field and press "Find All". The Search Result dialog appears. In localized builds the table header is not localized.
Hard-coded strings. :(
Andras Timar committed a patch related to this issue.
It has been pushed to "master":
fdo#80098 make header of Search Result dialog localizable
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.