How to find which file text on my website's home page is located?

I want to know which file in the server a particular line of text on my website is in.

I have tried inspecting the element and also downloading the backup and searching for the string in the files. There are too many files to check them all.

The website is coachingadda.com and the text string is "Find Tutors for Science, Maths, Commerce, English and other subjects. Can't find a tutor? Post your very own tuition request"