Hi @spletsx and welcome to the Open Targets Community! 
As mentioned in a previous post, we don’t currently have descriptions for each table and column in our data downloads.
We are looking for ways to document our datasets better, and/or provide schemas to help our users interpret our data better, however considering that the number of columns are in the hundreds, this is not a straightforward problem (especially if you consider how to make sure these descriptions are always up to date). In the meantime, if you could not find answers in our documentation, you can always ask here.
Is there a specific table or column you would like to know about?