It can be quite confusing, as Marklin (Maerklin) produced 'gauge 1' products before acquiring the LGB brand..
Especially disappointing if you buy a Marklin gauge 1 product, thinking it is 'G' scale.. It tends to be a little small.
Personally, I use the terms 'Marklin/LGB' to refer to post take-over items (especially decoders) and 'LGB' for everything before..