|  | Files in this directory are data for Go's API checker ("go tool api", in src/cmd/api). | 
|  |  | 
|  | Each file is a list of API features, one per line. | 
|  |  | 
|  | go1.txt (and similarly named files) are frozen once a version has been | 
|  | shipped. Each file adds new lines but does not remove any. | 
|  |  | 
|  | except.txt lists features that may disappear without breaking true | 
|  | compatibility. | 
|  |  | 
|  | Starting with go1.19.txt, each API feature line must end in "#nnnnn" | 
|  | giving the GitHub issue number of the proposal issue that accepted | 
|  | the new API. This helps with our end-of-cycle audit of new APIs. | 
|  | The same requirement applies to next/* (described below), which will | 
|  | become a go1.XX.txt for XX >= 19. | 
|  |  | 
|  | The next/ directory contains the only files intended to be mutated. | 
|  | Each file in that directory contains a list of features that may be added | 
|  | to the next release of Go. The files in this directory only affect the | 
|  | warning output from the go api tool. Each file should be named | 
|  | nnnnn.txt, after the issue number for the accepted proposal. | 
|  | (The #nnnnn suffix must also appear at the end of each line in the file; | 
|  | that will be preserved when next/*.txt is concatenated into go1.XX.txt.) |