You can help other teachers from your school by sharing your rubrics. To do it is very simple, you only have to follow the steps described in this tutorial because the procedure is exactly the same: Compartir e importar estructuras de grupos.
In that case, you only have to share a column where you are using the rubric that you want to share and the rubric itself will be shared as well.
Using the common copy/paste procedure (using Ctrl + C to copy and Ctrl + V to paste) you can easily import rubrics from an Excel file. You only need to open your rubric in Excel and copy the content that you want to have in Additio. Open Additio, go to the rubrics editor and make a right click on the first cell where you want to paste the content. Then press Ctrl + V to paste.
By now, you can only copy and paste the cells of the central part of the rubric, that are the most, but not the row and column headers.
NOTE: This option is only available in the web version