A method from subject would be handy for some clients. The current way how to get that is quite complicated:

   /*
     * supposes html tokens are always joined - just one joined sequence over the document!
     */
    public static TokenSequence<HTMLTokenId> getJoinedHtmlSequence(Document doc, LanguagePath languagePath) {
        //find html token sequence, in joined version if embedded
        TokenHierarchy th = TokenHierarchy.get(doc);
        List<TokenSequence> tslist = th.tokenSequenceList(languagePath, 0, Integer.MAX_VALUE);
        if(tslist.isEmpty()) {
            return  null; //no such sequence
        }
        TokenSequence first = tslist.get(0);
        first.moveStart(); 
        first.moveNext(); //should return true
        
        List<TokenSequence> embedded = th.embeddedTokenSequences(first.offset(), true);
        if(embedded.isEmpty()) {
            //try forward bias if we didn't find anything backward
            embedded = th.embeddedTokenSequences(first.offset(), false);
        }
        TokenSequence sequence = null;
        for (TokenSequence ts : embedded) {
            if (ts.language() == HTMLTokenId.language()) {
                if (sequence == null) {
                    //html is top level
                    sequence = ts;
                    break;
                } else {
                    //the sequence is my master language
                    //get joined html sequence from it
                    sequence = sequence.embeddedJoined(HTMLTokenId.language());
                    assert sequence != null;
                    break;
                }
            }
            sequence = ts;
        }
        return sequence;
    }