Related in terms of being easy to search for, I use the abbreviation "TK" as a placeholder for text or incomplete code. Took this from the publishing industry (my partner worked in magazines) -- it's a combination that does not appear in regular English and so is easy to both see and to use search tools for.
TK is a semi-well known widget toolkit/GUI toolkit which came from TCL and today it's the default toolkit for Python. Nothing fancy, just basic menues/buttons and widgets, but they get the job done in a hurry.
