I'm aware of Should we introduce a new tag for qgis + Sextante?, but it doesn't seem to have had a complete implementation, even though it is tagged as status-completed.
You may know that the processing framework SEXTANTE was implemented in several GIS software such as gvSIG, gvSIG CE, ArcGIS, QGIS, and even 52n-WPS. The current description of sextante tag doesn't reflect such diversity.
There is also the qgis-processing tag, which must be preferred for the former SEXTANTE (now Processing) plugin in QGIS.
Do you have any suggestion to improve this?
I've posted an answer with my proposal.