In their simplest form, SDF files include a molecular structure with the .mol format.
But SDF files offer more possibilities, in particular they allow to add meta data called "Tags" below the ".mol" part of the file.
For more information on SDF format see ...
A SDF tag, has the following structure:
> <TAG_NAME> ... tag content line 1 ... ... tag content line 2 ... ... tag content line 3 ... [Empty line to indicate the end of the tag]
For more information on SDF tags and how to read/write them see ...
The working group decided to use a set of tags to include the NMR data extracted from the NMR spectra in SDF files.
The labels of the tag all start with "NMREDATA_".