Wikipedia
Tunnbröd (literally "thin bread") is the Swedish version of flatbread and properly belongs to northern Swedish cuisine where housewives share a common bakery to produce it. Tunnbröd can be soft or crisp, and comes in many variants depending on choice of grain, leavening agent (or lack thereof) and rolling pin. The dough is made from any combination of wheat, barley and rye; the leavening agent can be both yeast and ammonium carbonate.
Soft tunnbröd is commonly used as a wrap for other food, not unlike a crêpe or tortilla. A popular fast food dish is soft tunnbröd rolled around mashed potatoes and a hot dog, known as tunnbrödsrulle (tunnbröd roll).
Another traditional old Swedish method of eating soft Tunnbröd is burrito style, combined with mashed potatoes and roasted herring.
Traditionally, tunnbröd is eaten with Surströmming (fermented herring) and as dopp i grytan (lit. "dip in the pot")- mostly a spiced soft bread is used for this -, where the bread is soaked in the stock left from cooking the Christmas ham. Crisp tunnbröd differs from knäckebröd in being thinner and more compact, containing fewer air bubbles.
The consistency and taste of thin bread can vary a lot. This is usually because recipes and preparation of the bread can vary a lot depending on bakery. Traditionally housewives would keep recipes a closely guarded secret only shared with other family members.