use the app-office/libreoffice{,-bin} implementation for extensions
Name Category Description
barcode app-officeext Extension for reading barcodes
ct2n app-officeext Extension for converting text to numbers
dmaths app-officeext Mathematics Formula Editor Extension
languagetool app-officeext Style and Grammar Checker for libreoffice
ooo2gd app-officeext Extension for export to Google docs, zoho and WebDAV
ooofbtools app-officeext Open/LibreOffice extension for the FictionBook2 format with validation
sun-templates app-officeext Collection of sun templates for various countries
texmaths app-officeext LaTeX Equation Editor for LibreOffice

Thank you!