Fitting in new stuff in a finished exectutable (the ROM) is normally impossible since it would spill over other needed stuff and overwrite it, potentially making the game unplayable.
So, people either replace existing data with data exactly the same size or smaller, or would just hook new stuff (either text/graphic/etc assets or assembly programming) then alter pointers so that the new stuff is referenced.
Of course, altering ROMs often also involves decomposig the data to individual parts to identify them, extract them, modify them separatedly and reinsert them.
This is why modders and translators of retro games have come to accept the hacker label because it fits these aspects of what they do.
Not hacker in the sense of people breaking up locks on digital safes to steal stuff - though some game publishers often use this nuance to refer to romhackers to villify them in cases they don't serve their business interests.
That said, it's shameful Jonesy47's passion for this mod many of us are eagerly expecting, is met by mean spirited messages where the obvious intent is to drag down his efforts, and it's about:
a - the mod is late
b - telling people interested in the original Metal Gear canon to go play instead the official corporate-approved shiny new non-retro legal(tm) releases
c - minimal-effort attempts to call people plagiarists and scummy thieves
And on top of that, you're trying to police what people do here?
Rom hacks are done without the consent of the original creators and publishers. These creators are aware of this and turn a blind eye over it as long as no actual ROM data or part of it (example: DQ7 script) is being distributed, in fact they even support it as it improves the visibility for their retro stuff (Square's comments on FF5 at the PS1 days, Reggie and Miyamoto on Mother 3, LunarIPS automatic hacks from niconico in Super Mario Maker...).
Even if they want to support mods openly, they are afraid iPhone clone game devs will take advantage legally from a formal authorization to use their assets. Or fear to lose the trademark due to the stupid US copyright laws.
This site specifically mostly deals with retro games who are for companies just bibliography footnotes and archeological relics with no intent for preservation or improvement (if they even can, considering pixel edition and retro assembly expertise has been mostly lost from the industry).
So remove that stick already and deal with it - No one is interested in high-horse riding lessons about how to reduce "(non-issues i deem now big problems) in the scene".
Your nostalgic blackout boycott of mods failing to abide by your "limitations" and being "dangerous"?
1 - it doesn't apply here : for someone trying to not to assume the weight of your mean-spirited jabs at a hardworking productive member because "i put them there but they're striked", you're sure spending a ton of time calling out a "plagiarism" problem specifically in the "scene.
Last I'm aware of, he wasn't from the "romhacking scene", that youtuber who just had a funny artwork that you deem he and all those who ever did deviantart fanart won't escape your plagiarism watcheful vengeful falcon eye and get away with it just because those company lawyers shrugged off these crimes.
(or maybe he did and your stellar research skills strike again?)
So I assume this is just you doubling down on your rude manners.
2 - this stuff is often mentioned in the readme, in the special thanks section. Casual verbal 'okay' and common courtesy is the norm. There's a culture of sharing. They don't need your bloated creative license and witchhunts/boycotts/blackouts from the good-old-days. Or arbitrary limitations that the "borrowed" assets must come from the same series - I'll use that Earthbound font wherever I like, thank you very much.
I'm rather interested in what our self-appointed policeman contributed to the romhacking scene beyond his lawmaking skills.