New! Click any icon in Search view to open a (crude) editor. Here you can see it extra-big and move some endpoints around. Click the path lists on the left to highlight one; drag blue or yellow handles around to tweak; click Save to see it in the grid on the page; click Export to save to your local system.
Select some or all of the files you want to test and drop them where it says Drop SVG Files Here. Once you have at least one marker up the drop target box should say Add More; drop 'em if you've got 'em.
Top row of buttons (search, header, and map) change the size and border, and show them on a map for map.
If you're in Header mode you can click individual buttons to see what they might look like disabled.
Middle thing is a background-size slider so you can see the SVGs larger and smaller inside the individual marker.
Next is Shuffle, which will randomize the order of background images over the same color set. We will have a certain amount of control over this in production, meaning if we know we have 25 markers we could nudge some of them towards certain colors, maybe get the red background for Medical and the blue for Water.
Colors are assigned hues from 0 to 359, spaced as far apart as possible. (Nerd info: computed colors are the hue with saturation and value modified so a white background image will always be visible at Web Content Accessibility Guidelines level AA.)