I doubt this is actually possible, but unless I ask, I won't know!
It would be excellent if the LED of the Flic button was accessible to program in some way - even if it was with restricted patterns so as not to be confused with the regular not-connected pattern.
Here's my use case, I'm sure there may be others:
Using Node-Red and a Raspberry Pi I am controlling my Hue Lights in my home - as the sun goes down, I've been automatically changing the colour of my hue bulbs from a blue/white light, to a yellow light - but before this happens, I've been flashing my hue bulb red, and Node-Red then waits for a click of my Flic button before beginning it's transition. No click - the transition continues, with a click, the transition is terminated and it stays on the whiter light.
It would be excellent if the LED on the Flic button itself could flash for a similar 'deadman switch' kind of scenario, when a hue bulb isn't handy or isn't related to the task to be achieved. For example, my coffee machine via a Wemo is set to turn itself off at 9am, but if I'm at home and haven't had a coffee yet, and am sitting at my kitchen bench, it would be great to have a 'warning' flash via my flic, and be able to intervene in order to stop the machine turning off.
As I said, probably a pipe dream, but would be a small and very cool way to add a significantly powerful feature to the Flic buttons.