While 3ventic's answer is the easiest way, there is a way to do it which is fully offline and more garunteed than Waddling Pig's answer (as not all games have that steam_appid file) however this will only work for games you have downloaded as this method has you look in the steamapps folder.

awk with '-' set as the delimiter to print the columns formatted with the name of the game followed by the ID number.

sed to strip the line up to and including the '_' (leaving the appid), replace the tabs with a single space, remove the double quotes, remove the word 'name', replace the first space after the id number with a '-' (a character that is not found in any game names).

acf with the appID in them followed by our mathed grep pattern 'name' and the name of the application. The lines it returns are the filepath/name of the.

grep for lines containing 'name' in all the.

Your path to /steamapps/ may vary if you install your games to a non default place. A list of all your installed steam apps and their appID's can be obtained easily with one line of BASH offline using grep, sed and awk to look at the appmanifest files in Steam/steamapps/(on Linux/Unix)

Steam chat history folder