I've seen a few variations used, and upon asking the question on Twitter (as a poll limited to 4 options), some came back with a few other suggestions.
Preference for application item prefix in #orclapex ?— Scott (@swesley_perth) July 21, 2016
The final tally based on the replies (we'll see how pasting from Excel goes...)
F_ | 15 | Inspired by APEX team, no doubt. +1 for me | |
APP_ | 10 | Fair call, but could match built-in | |
G_ | 6 | Global, clever. One person combines this with A_ for application scope. | |
{project} | 5 | To match the prefix on your tables, right? | |
AI_ | 3 | Can't deny the provenance | |
{none} | 3 | This is dangerous, potential clash with built-ins | |
A_ | 1 | Based on item scope. |
I remember some chatter recently about a community sourced standards document for APEX being kicked off on StackOverflow. Perhaps mini surveys like this can help shape projects like that, or maybe it fits into the oraopensource activities.
Either way, this sort of discussion is surely healthy for the community, eking out any important considerations in sometimes seemingly trivial matters, or "bikeshedding" is a term I heard recently.
I can't say I've tried creating application items (or substitution strings for that matter) that are the same as a pre-defined substition string, but surely it would be detrimental.
You never know, even the Oracle APEX development team may decide a thing or two from community responses. I certainly know what my next poll topic will be, now the Fire on Page Load default No campaign is over ;p
ps - more 2015 survey results to come. The next question was on instrumentation, so a few juicy points to make there.