https://addons.opera.com/en-gb/extensions/details/umatrix/
uMatrix extension - Opera add-ons
add onsumatrixextensionopera
https://www.r-project.org/nosvn/R.check/r-devel-windows-x86_64/Umatrix-00check.html
Check results for 'Umatrix'
check resultsumatrix
https://cran.mirror.garr.it/CRAN/web/checks/check_results_Umatrix.html
CRAN Package Check Results for Package Umatrix
check resultscranpackageumatrix