So I dug a bit deeper. There's a document that I cannot get the link to show properly, but if you Google for "ads-b protocol header" you will find a draft technical manual "UAT-SWG02-WP04 -Draft Tech Manual V0-1 .pdf" on
www.icao.int that shows all fields in ADS-B messages. From page 43 onward there's an explanation of the "Mode Status element" that contains the "Emitter Category"field. They use "Base-40 Decimal" numbers that do not translate directly to the hex table from Funkwerk, but the list of possible categories resembles what Funkwerk uses:
0 No aircraft type information
1 Light (ICAO) < 15 500 lbs
2 Small -15 500 to 75 000 lbs
3 Large -75 000 to 300 000 lbs
4 High Vortex Large (e.g., aircraft such as B757)
5 Heavy (ICAO) -> 300 000 lbs
6 Highly Maneuverable > 5G acceleration and high speed
7 Rotocraft
8 (Unassigned)
9 Glider/sailplane
10 Lighter than air
11 Parachutist/sky diver
12 Ultra light/hang glider/paraglider
13 (Unassigned)
14 Unmanned aerial vehicle
15 Space/transatmospheric vehicle
16 (Unassigned)
17 Surface vehicle —emergency vehicle
18 Surface vehicle —service vehicle
19 Point Obstacle (includes tethered balloons)
20 Cluster Obstacle
21 Line Obstacle
22 (reserved)
...
39 (reserved)