Let’s assume you can fully describe your current project and its configuration, tools, etc. And let’s also assume you can clearly describe the desired outcome and the constraints you must work within.
Example: “I have to make my app perform specific function X. My project currently is written in language A, using frameworks B and C. The project must be able to run under environment D. Extensions for D can be installed from repository E. I am NOT allowed to write parts of the code in language F, add any framework extensions to framework C, or outsource the task to project G. I CAN use any available framework for framework B from public repository H as long as it will function in environment D.”
An example of a “specific function” would be high-level but very narrow: “I need to produce a PDF of a Word document uploaded by a user”, “I need to combine five sound files in .WAV format into a single .FLAC file in a given order”, “I need to dynamically resize a JPEG image of any size downloaded from a URL to 100×50”, etc.
My challenge is that researching a means to the desired outcome will always result in extremely specific posts (on many sites, not just SO/SE) that do not and cannot apply to my environment and constraints. Or, I might find posts saying “You can’t do that” but they’re 13 years old – in software development a year is a long time for new frameworks, libraries, enhancements, etc.
So, I may be looking for a software library (software recommendations), but perhaps framework B already has the capability and I just need pointers on how to leverage it (stack overflow), or maybe my overall high-level design could be altered to meet the requirement without outstepping the constraints (software engineering). Basically, I could see my question applying to multiple SE sites depending on the answer.
Simply asking “how can you achieve X” would be too broad, but as soon as you add in all your details (“I must use language A and frameworks B and C, etc.”) then any generic response is not going to apply. So basically, I have specificity, but not the kind of specificity that applies to any one single SE site.
TL;dr: Where can you ask a question about a high-level functional requirement that must exist within a set of constraints, where you’re not sure what the possible options are and therefore you can’t get specific enough about which SE site to post it on?