match underlying Chromium version to the compatible ffmpeg and widevine version, repeat this procedure for all installed variants of Opera browser by using temp cache for downloaded assets

CHANGELOG.md

@@ -9,9 +9,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- version-aware ffmpeg selection: detect Opera's bundled Chromium version and download the matching nwjs-ffmpeg release instead of always using the latest
+- per-variant Chromium detection via binary inspection (`get_chromium_major`)
+- ffmpeg download caching: skip re-download when multiple Opera variants share the same Chromium version
+
 ### Changed
 
 - universal shebang bash interpreter to safely find bash on `$PATH`
+- Widevine CDM is now downloaded once before the main loop instead of redundantly per variant
+- release data is fetched once upfront (`?per_page=50`) and reused for version matching
 
 ### Removed
 
@@ -20,3 +26,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - in the preflight check: Prefer our user-friendly error messages while avoiding double error message from the operating system by redirecting also `stderr` to `/dev/null`
 - potential runtime error: prefer `command -v` over `which`-command, which can have different behaviour on different Linux distributions and always use the first result in `PATH` independently of multiple defined commands
+- `grep` error when `CDM_FLAG` starts with `--` by adding explicit end-of-options separator (`grep -qF -- "$CDM_FLAG"`)