My passport got exposed to heat, due to a laptop battery heating up. The passport is intact, not showing any damage. During my travels, will the MRZ be scanable, or would this create any issues? If it's not scannable, will they check manually?
The MRZ is just some printed text on the bottom of the identity page - this is what it looks like (image from wikipedia):
Your passport's version is called td-3 (the first example).
So as long as that ID page is not distorted the MRZ will be readable.
i downloaded some mrz scanner app. i shared my mrz . is it safe. any chance duplicates are made out of this.
The point of the MRZ is to standardize information that is written on the same item where the MRZ is printed, so its quickly readable by a scanner.
The MRZ is not a security feature.
As your passport MRZ contains some important information (like your nationality and passport number) it is best to deal with it like any other confidential piece of information.