Add dev doc about localization

diff --git a/support/doc/development/localization.md b/support/doc/development/localization.md
new file mode 100644 (file)
index 0000000..3cf7975
--- /dev/null
+++ b/support/doc/development/localization.md
@@ -0,0 +1,32 @@
+# Application localization documentation
+
+Source files are in `client/src/locale/source` and translated files pulled from [Zanata](https://trad.framasoft.org/zanata/iteration/view/peertube/develop/languages/fr?dswid=-1605) in `client/src/locale/target`.
+
+## Generation
+
+Will generate XLIFF files for Angular and escape inner elements in `source` tag because Zanata does not support them.
+
+This script will create `player_en_US.xml` XLIFF file using custom strings (VideoJS plugins) and strings from `videojs_en_US.json` file.
+
+It will also create `server_en_US.xml` XLIFF file using custom strings (defined inside the script, we did not find a way to extract them from TypeScript server files).
+
+```
+$ npm run i18n:generate
+```
+
+## Upload on Zanata
+
+Push source source files (en-US) on Zanata:
+
+```
+$ zanata-cli push
+```
+
+## Pull translation
+
+Pull XLIFF files from Zanata, and unescape them (so we retrieve inner elements in `source` tag, used by Angular).
+A hook converts `player` and `server` translation files to JSON (needed by Video.JS, and our application to have efficient runtime translation).
+
+```
+$ zanata-cli pull
+```