Firefox - cryptic symbols

[#1]

I'm getting a few cryptic symbols in my Firefox URL toolbar:-

Apparently the broken Lego brick is an indication that I can choose to run an outdated version of flash (if I choose to).

I don't get this on other sites.

[#2 · Accepted solution]

if I install the latest Flash plugin I'm invited to allow it for this site.

I'm not curious enough to allow it.