Maggi seasoning is synonymous with the brand's "Maggi-Würze" (Maggi spice), a dark sauce which is very similar to East Asian soy sauce but the amount of soy in it varies in different parts of the world. For example in the UK, if you buy the Malaysian version, it does contain soy sauce, but the USA version does not.
It was also introduced in 1886, as a cheap substitute for meat extract. It has since become a well-known part of everyday culinary culture in Switzerland, Austria and especially in Germany. It is suitable for vegetarians.