mention explicitly that `go.mod` provides enough information for reproducible builds without `go.sum` being a lock file. (Some people think of `go.sum` as a lock file).
update MVS example, including more explicitly work in the phrase "100% reproducible builds"; also draw stronger contrast between `go mod tidy` vs. `go build`; move proxy discussion into FAQ (prior level of detail didn't really belong up front)
flip order of explanation for why `go mod tidy` is useful, and provide a more targeted pointer to explanation how `go mod tidy` reflects all possible build tags/OS/architecture combinations
add a v2+ example to the first go.mod example; remove sentence about ability to quote module paths (given its usefulness is more a corner case that doesn't need to be covered so early in introductory material)
add 3 more FAQs on: why `go get example.com/cmd` fails with error `cannot find main module` when run outside of module; how to track tool dependencies of a specific module; and summarize the GO111MODULE/GOPATH behavior
expand the 'Semantic Import Versioning' section, including quote the old versioning advice from the FAQ, quote the import compatibility rule, attempt to tie them together
include reference to pseudo-versions in module query introduction; use friendlier example modules for the intro `go.mod` shown and clean up related text
mention option of a `v2.0.0` release on master along with the subsequent suggestion for a v1 branch (option outlined in official proposal FAQ); also provide an explicit pointer back to this v2+ discussion from the 'Releasing a module' section; adjust the older "still in flux" comment regarding v2+ modules
in 'Semantic import versioning' concepts section: include more explicit pointer to semantic import version section of tip documentation; mention the actual older versions 1.9.7 and 1.10.3 that now have minimal module awareness; mention that the '/v2' subdirectory approach allows for compatibility with even older Go versions and make the description a bit more specific
add a recommendation to typically check in `go.sum` (e.g., see https://twitter.com/FiloSottile/status/1029404663358087173); also mention that `go.sum` is not a traditional lock file, which is a question that comes up somewhat frequently