What's the specific meaning of parameters in the ‘SBGRO047.SPE’ file?

[JongChao]

Hello,
I am learning the DSSAT-CROPGRO-Soybean model.
I would enquire about the relationship between temperature and soybean photosynthesis within this model. I had studied the document ‘DSSAT45 Volume 4.pdf’ and other publications. However, I don’t understand the specific meaning of many parameters in the ‘SBGRO047.SPE’ file.
How should I get some notes about the parameters in this file?
Thanks for your help in advance!