Hi Sara
Thanks for your help with this.
I do have an 
additional question though. In Moodle you can combine letters/words and 
curly brackets, eg. you can write relevant{$a}string, without spaces 
before or after the curly brackets. What is the rule when it comes to 
h5p placeholders? 
Can I use :lib-translatedword, translatedword:lib, translatedword-:lib or :libtranslatedword
I ask because I sometime combine a word and a placeholder in my translations. In Danish we have a lot of 'doubbled' words. Eg. I have translated a string like this:
[Missing translation :key] → [Mangler oversættelses-:key]
In this case I have chosen to use a hyphen
 between my Danish word and the placeholder, in the hope that it will be
 okay. Normally in Moodle I might have translated the string containing curly brackets without the
 hyphen.
In addition I might be tempted to write 
%libtypen skal...
which would work with placeholder with curly brackets.
Another example:
The :property value can only contain numbers. → :property-værdien kan kun indeholde tal.
 Thanks in advance
Bente