The linked XKCD's are #225 <i>"Open Source</i>" and #239 <i>"Blagofaire"</i> (the one with Cory Doctorow in a hot-air-balloon). Stallman-with-a-katana also shows up in the five-part arc #341-345 <i>"1337"</i>. (I don't know if there were others?)<p><a href="https://xkcd.com/341/" rel="nofollow">https://xkcd.com/341/</a><p>I'm inferring the real-life katana was a joke based on #225 (and maybe Randall Munroe wrote it in again in reference to the real-life object).