Explanation for damage chart

[Lysander]

Hi everyone, I found this damage chart on the wiki and it looks very helpful:
https://wiki.project1999.com/Statistics#Ratios

But I wanted to know, how did they get this information, and is it still accurate and reliable? Is there a corresponding chart for 2h? Is there any other way to compare weapons besides parsing it yourself?

Also, what does the number of 0.83 or whatever mean anyways? The chart has no explanation.