What rule of grammar does this sentence break? (I mean the "does" part of the following sentence)
What does the status indicators mean?
Also, why does english.stackexchange.com have a code option for formatting... Maybe BASIC or Apple script qualifies as English.
Does is singular. Indicators is plural. To use them together, as in your example, is to violate the subject-verb agreement of the sentence.
To create proper subject-verb agreement here would entail either changing the "does" to plural ("do"), or changing the "indicators" to singular ("indicator").
What do the status indicators mean?
What does the status indicator mean?
The first would probably be your choice, since I gather from the original example that there are in fact more than one indicator.
However (this is important), if the example question is asking what the phrase the status indicators means, the grammar is correct, but the phrase in question should be inside quotes or italicized:
What does the status indicators mean?
Subjects and verbs corresponds in person and number.
You don't normally write "I does", as does is used for the third singular person; are is not used for the first person singular, but for the plural person or the second person singular.
That is true also when using the negative form, and writing questions.
The sentence you wrote should be written "What do the status indicators mean?" or "What does the status indicator mean?" The subject of your sentence is not status (which is singular), but indicators (which is plural); status is an attribute, a noun that is used to alter the noun that follows it, in the same way expiration in expiration date is used as attribute of date. Status could be the subject in "What is the current status?" and in that case you use is because the subject is the third person singular.
Your sentence could be correct if it were "What does 'status indicators' mean?" because there is an implicit word being used: "What does the 'status indicators' phrase mean?"
