First, a word of gratitude. Thanks for the extra flags!
Question: I am in the process of replacing the blue flag and have it stand for something else. My first step will be to erase the blue flags every time I come to one. Is there a faster way of doing that? Can I eliminate all blue flags so I can begin to use it the way I wish to use it starting from now? Many thanks!
If you go to “Browse”, you should be able to see in the sidebar the category “Flags”.
By selecting one of the flags, all cards marked with that flag will be displayed. Then use Ctrl + A to select all the cards, right-click on any card, go to “Flag” and, at last, uncheck or check the boxes as desired.