The "Warning" quality gate value has been deprecated in 7.6.
It means that analysis starting from 7.6 will have no more warning, the "Warning" value in the Quality Gate facet of the Projects page will always be 0 when all projects will be re-analyzed.
When this situation arrive, the "Warning" value of the facet must disappear from the facet.
At startup, execute a daemon executed every day that will compute the number of projects in warning and store the value in an internal properties.
When the value is zero, the daemon will be stopped.