Decide at build time if a per-language logo is available, otherwise fall back to the default logo in english.
|asseturl filtering checks if the file exists. If not, it falls
back to the default.
A filename convention where fields are separated by underlines ("_") and that the last field before the extension is the TPO's language code.
That the fallback (default) logo is set to the english version (even if it does not exists).
This implementatio does not require a custom databag (!28 (closed)).