i have a question in regard the timer of the limesurvey. where i can find the source code for the timer or could you please provide it? i want the timer to be pinned in the title/description of the survey, like countdown for all questions/groups

You don't need to hack the source code for this. Some JavaScript to move the timer from question X to the top of the survey should be sufficient.
Such JS can be placed at the template.js file of your template.