Damn

Someone came up with a reasonble explination: https://www.tumblr.com/adobe-outdesign/tagged/this%20post%20has%20everything...%20language...%20mistranslations...%20impregnated%20goblins...

This is a hilarious mistranslation actually. I suspect it originally said something along the lines of “Impregnerad mot vatten”, i.e. “Water proof”.
Impregnering is the process of making a material resistant to water/heat. The swedish word for water (vatten) is similar to the word for goblin (vätten) so I guess there was a mixup.

It’s also possible “goblin” was used as a translation of “tomte”, the creature depicted riding the wagon, with impregnated referring to the matches being made of impregnated wood. The implication of the two words combined in English might not have occurred to whoever designed it, since “impregnerad” isn’t really used in that meaning in Swedish.
“Impregnerad mot vatten/vätten” would more likely have been translated as “impregnated against water/goblin”. The absence of “against” would make it very clunky in both English and Swedish, which kinda points against it.

Did some Google searching myself:
The JWT stands for Jönköping Westra Tändstickfabrik, one of the major matchstick factories in Sweden before they consolidated into the Zyn company.
https://thoresmatches.se/tandsticksfabriker/jonkopings_westra_tandsticksfabrik.htm
You can see in the matchbox pixtures in the page above, that they did use the term "impregnerade" to refer to their chemical treatment on the matchsticks.
This article says that the impregnation treatment was beneficial because it made matches blow out quickly without smoldering:
https://thoresmatches.se/tandsticksfabriker/sakerhetstandstickan.htm
This post on the SomethingAwful forums seems to show an original photo of the match boxes, posted by someone with a Swedish username.
https://forums.somethingawful.com/showthread.php?threadid=3948652&pagenumber=9#post521474833
These matches don't seem to be recorded in many museums, so probably either a modern gag, a period knock-off, or genuinely a Swedish person who didn't realize that impregnerade had a double meaning in English.
There is a matchstick museum in Jönköping, Sweden that could probably answer.
- the fact that the factory was in jönköping means that there is a distinct possibility that the word "goblin" is a mistranslation of "vättern", which is the big lake jönköping sits on.
- Thanks for the research! I will send the museum an email and ask if they know anything.
  or genuinely a Swedish person who didn’t realize that impregnerade had a double meaning in English.
  Or perhaps someone who knew what they were doing (but more likely not). Perhaps a way to market them outside of Sweden, though that really depends on when this was.

How have I only now put together that that means the matches are impregnated as in water resistant or something.

Yeah they probably tried to translate "Vätterns impregnerade tändstickor" or similar, which means "The goblins/gnomes impregnated matches".
Possibly with a compound to make them light easier or burn steadier

So that's how JSON web tokens are delivered. TIL.

Now, let’s not kink-shame