github.com/tidwall/go@v0.0.0-20170415222209-6694a6888b7d/api/README (about)

     1  Files in this directory are data for Go's API checker ("go tool api", in src/cmd/api).
     2  
     3  Each file is a list of API features, one per line.
     4  
     5  go1.txt (and similarly named files) are frozen once a version has been
     6  shipped. Each file adds new lines but does not remove any.
     7  
     8  except.txt lists features that may disappear without breaking true
     9  compatibility.
    10  
    11  next.txt is the only file intended to be mutated. It's a list of
    12  features that may be added to the next version. It only affects
    13  warning output from the go api tool.
    14