Zebediah Figura (@zfigura) commented about dlls/wmvcore/async_reader.c:
struct stream *stream = arg; struct async_reader *reader = stream->reader; struct sample *sample;
WCHAR buffer[256]; HRESULT hr;
TRACE("reader %p, number %u\n", reader, stream->number);
swprintf(buffer, ARRAY_SIZE(buffer), L"wine_wmreader_stream_%u_read", stream->number);
SetThreadDescription(GetCurrentThread(), buffer);
Linux cuts off thread names at 15 characters (not counting the null terminator), which somewhat unfortunately makes all of these identical to each other and the deliver threads. Thus far I think Brendan had been trying to make the thread names distinct, if not per se trying to fit the entire name within 15 characters.