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.