readme

README.md

@@ -87,4 +87,48 @@ There are some branches that were forked from `main` for historical reasons, tha
 MAY be of interest situationally, but otherwise should be ignored.
 
 - `main-np`: Forked from the last commit using `eval` before `eval2` was the
-  primary interface into the interpreter. No longer actively developed.
+  primary interface into the interpreter. No longer actively developed.
+
+## Dev stuff
+
+### Local environment & CI
+
+Uses nixos.
+
+Install `nix develop` - https://nixos.org/download.html.
+
+Run `nix develop` in this repo to drop into the shell. Please ONLY use the nix
+version of `foundry` for development, to ensure versions are all compatible.
+
+Read the `flake.nix` file to find some additional commands included for dev and
+CI usage.
+
+## Legal stuff
+
+Everything is under DecentraLicense 1.0 (DCL-1.0) which can be found in `LICENSES/`.
+
+This is basically `CAL-1.0` which is an open source license
+https://opensource.org/license/cal-1-0
+
+The non-legal summary of DCL-1.0 is that the source is open, as expected, but
+also user data in the systems that this code runs on must also be made available
+to those users as relevant, and that private keys remain private.
+
+Roughly it's "not your keys, not your coins" aware, as close as we could get in
+legalese.
+
+This is the default situation on permissionless blockchains, so shouldn't require
+any additional effort by dev-users to adhere to the license terms.
+
+This repo is REUSE 3.2 compliant https://reuse.software/spec-3.2/ and compatible
+with `reuse` tooling (also available in the nix shell here).
+
+```
+nix develop -c rainix-sol-legal
+```
+
+## Contributions
+
+Contributions are welcome **under the same license** as above.
+
+Contributors agree and warrant that their contributions are compliant.