Currently many extension articles specify |needs-updatephp=no (i.e. maintenance/update.php doesn’t need to be run, because the extension doesn’t make any database changes or whatsoever), while many others do not. This information can be inferred from the extension.json file (for extensions that have this) by Module:Extension, but—to be on the safe side—the module outputs nothing if the answer would be “no” (just like when it doesn’t know anything about the extension). The current mixed situation is clearly inferior; the question is whether we want to include “no” for all extensions it’s known to be no, or we want to omit them, and display anything only if update.php does need to be run. I have no strong opinion on the question, just want to have it decided either way. (I saw related edits by Pppery and Shirayuki, what do you think?)
Topic on Template talk:Extension
As I said on my talk page, I personally don't see the point of setting it to no; running update.php unnecessarily does no harm, and I suspect if a page is silent on whether it should be run, the typical uninformed user would not run it.
I think that we do not need to set "No" for this template argument for the simple reason that this is not set consistently over all extensions documented anyways. Moreover you would run into even bigger confusion if it says "No" even though it shoult be "Yes" (See the issue described in this topic). So rather not set it at all than having an potentially incorrect information.
Does that mean I should implement Special:Diff/3889937/3897060, which would make the template ignore |needs-updatephp=no entirely?