Our work with the SIS is organised by milestones. Milestones is what we review at nearly each meeting. But some issues do not clearly belong to either the SIS line of milestones (for source code) or the Format-Recommendations line. And then they get slowly out of sight as new issues heap up. So this is the One Milestone to find them, to bring them all and in our scope to bind them.
The way to find issues without a milestone set is to search for is:issue is:open no:milestone