Hi and welcome. You sound like a tinkerer who's also ready to fiddle a bit himself, definitely helpful for using KM ;-)
Yes by all means, if your system allows it, use modern KM76. At least the old gecko version, and much better the current Goanna version. Not only the engine is much better with modern websites, but also internal KM-functions are better (mainly macrolanguage), and better compatibility with FF-addons. Unlike Firefox, newer KM-versions are still "adding" functions, instead of removing them (just 1 exception, the old UA macro, but guess the dev wanted KM more visible in statistics ;-))
And that was very wise to not override omni.ja accidentally. There are 2 files of this name, in root-folder and in browser subfolder, and they are the very core of the engine. Always a good idea to inspect zip-files before blindly tossing them into the folders.
And also a good idea to take a quick glance inside the macros kmm files, just to get at least a rough idea what they do. E.g. have seen some that secretly toggle on Javascript permanently, or load scripts from 3rd-party webservers, which I'd like to know at least. Or rather, prefer to modify myself.
EXTENSIONS:
There are a LOT more macros available for KM as complicated FF-addons. Look in the extensions subforum. Most recent ones there, just sadly a bit hard to find without tags and categories. There's also a separate project "kmext.sf.net". Much handier to find stuff, sorted by category, but not maintained anymore since years, and most extensions 10-15 years old. Plain macrolanguage (*.kmm) still works in modern KM, but ported FF-addons can be broken.
Complex xpi-ADDON packages in 7z:
Definitely unzip and look inside before installing, as you did. For example have seen special KM-packages for FF-addons, which contain the xpi inside folder "KM/extensions". Effect: supereasy installation, but makes those addons completely invisible on about:addons. Very confusing for users. Or other zips may contain xpi-addons in subfolder "KM/browser/extensions". Also to make installation easier, just unzip and drop, and those addons do show up on about:addons - just have no "Remove" button. All fine and no prob, just as long as users are *aware* about those minor differences. Where to find installed addons and how to remove them again if wished, or how they can install xpi-addons "normally" like Firefox (open about:addons and drag-drop an xpi-file inside, or use the button there to install from a local xpi-file, both methods will install it in the PROFILE). Just hardly anyone knows such minor details, and is confused instead.
USERAGENTS:
One of my personal favorite improvements: KM-Goanna (74+76) has finally activated Mozilla's NATIVE function to send websites different useragent-strings by DOMAIN! The engine function for those site-specific useragents was already contained since KM74, just not initialized. All which this function needs out-of-box are some prefs in about:config, or for convenience a menu macro like useragents2018 can be used, just for easier setting prefs.
Note that this NATIVE domain-UA function gets killed again when installing any complex useragent "addons", meaning "xpi" or components files, not just macros (*.kmm). Those "addons" use their own settings, in general they make it impossible to fake the global useragent string, instead each and every page where you toggle the UA will get stored in the profile. And older ones can't even fake the UA for javascript checks too. I can't stand all of this, but that's just a personal preference, and rodocop loves it exactly the other way around ;-) But the next prob is that most users are not aware how those 'special' addons work exactly, often not even aware those are even installed in their own KM-version, and keep stumbling over instructions for the native methods, which don't work anymore. Then think they were just too stupid or all UA functions broken etc. and just give up completely.
But the native function also has a little trap, since KM-Goanna: unknown to most users, lots of domain-UAs are already predefined in KM! (Unfortunately hardcoded inside omni.ja, would be much better defaults/pref files, but again opinions differ) Those prefs are visible and editable on about:config. They do help a lot for problematic websites, but need occasional updates. After awhile they become outdated, then users are clueless why those websites are now broken, even if they toggle the global useragent string.
PORTABLE K-Meleon:
If the root folder contains an empty file "profile.ini", K-Meleon will look up all profiles inside its root folder, this makes it portable. If that ini-file does not exist, K-Meleon will instead look for the profiles folder in the system's appdata folder for that user.
This ini-file can also be created or removed any time again later, to easily switch between modes at next startup if wished.
This "portable" mode only refers to the location of the user profile folders, and where K-Meleon itself writes stuff, nothing else. It is not a "stealth" mode, it can not prevent any traces written elsewhere by the system or in the registry.
A trap: some time after XP (Vista or Win7?) the Windows versions were becoming more and more restrictive towards user-installed programs, and in order to still allow older portable apps to run, Windows introduced some 'clever' new workarounds. This can cause problems when portable programs are installed into protected folders, especially the official "programs" folder. The system lets those programs think they were still writing settings inside their root folder there, yet in reality the system secretly redirects all write-attemps into another dedicated user folder outside! But those redirects don't seem to work equally well for READ attempts, so some users found the browser is writing stuff, but cannot find it anymore later!
To avoid such probs most power users prefer to install KM outside of protected folders, but I suppose it would probably suffice to just give the necessary subfolders more permissions manually. Especially profiles folder, but also the skins folder and perhaps others.
ADBLOCK:
a neverending chaos, sigh, and am not very familiar with it either, being stuck on a too old OS myself. There are already several detailed posts out there describing the crucial basics, between the various KM-versions and various native functions and various optional FF-addons... Strongly recommend to look those up again. Here just one thing:
There seem to be 2 fundamentally different methods for adblocking:
1) For handling HIDING rules by css, KM always contained since ancient times the file "/chrome/adblock.css", it works from inside the current USER profile folder. The old template is still dating from 2006 (!!) and I suspect it only understands those era's syntax rules too. For this function there is a switch in F2 > Page Display> Content Filters, and also in the Privacy Menu "Block Advertisement"
2) For handling real BLOCKING rules, a plugin or addon is needed. Younger KM-versions contain natively /kplugins/adblock.DLL for this purpose. Yet - NO GUI and no template contained, searching anything inside the browser completely futile. The GUI-macro that rodocop linked above should long since be included by default, but that's just one of far too many unnecessary GUI probs. And even with this menu macro, that adblock-plugin is still extremely lacking GUI-wise. It's not even possible to add new rules during the current session, or import an updated list!
To make things yet more confusing, recent KM-versions contain pre-installed rule templates for adblockplus already - yet not that addon itself! The popup at first KM-start refers only to the native adblock.dll. The one without any templates and GUI. Sigh. So typical for unnecessary GUI probs.
Sigh, didn't mean to write such a novel, only planned a few remarks - where does time go?!
And just some weeks ago have already written a bunch of "beginner tips" somewhere... There's so much handy stuff but hidden without GUI, especially: try right-clicking on toolbar buttons! Many contain an additional menu, although not noticable without additional arrows...
(sig)
New unofficial K-Meleon 76.4 (KMG76.4) available, in own subforum.
Based on Goanna engine, called 'test' builds forever but more stable as 75.1 acc. forum members. It's 1-2 generations ahead of predecessor KM76RC-2016
K-Meleon FAQ (link missing in forum sidebar)
Tips&Tricks -
Learning new stuff every day
New to K-Meleon?
What do you like? What not?