#history-panelmenu {
	list-style-image: url("./svg/history.svg") !important;
}
#PlacesChevron, #nav-bar-overflow-button {
	list-style-image: url("./svg/chevron.svg") !important;
}

<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
  <path fill="context-fill" fill-opacity="context-fill-opacity" d="M8 0a8 8 0 1 0 8 8 8.009 8.009 0 0 0-8-8zm0 14a6 6 0 1 1 6-6 6.007 6.007 0 0 1-6 6zm3.5-6H8V4.5a.5.5 0 0 0-1 0v4a.5.5 0 0 0 .5.5h4a.5.5 0 0 0 0-1z"/>
</svg>

<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
  <path fill="context-fill" fill-opacity="context-fill-opacity" d="M8.707,7.293l-5-5A1,1,0,0,0,2.293,3.707L6.586,8,2.293,12.293a1,1,0,1,0,1.414,1.414l5-5A1,1,0,0,0,8.707,7.293Zm6,0-5-5A1,1,0,0,0,8.293,3.707L12.586,8,8.293,12.293a1,1,0,1,0,1.414,1.414l5-5A1,1,0,0,0,14.707,7.293Z"/>
</svg>

:root:not([uidensity="touch"]) {
	--bookmark-block-padding: 1px !important;
}

#personal-bookmarks {
        margin-top: -4px !important;
}

#tabs-newtab-button, #TabsToolbar #new-tab-button {
	list-style-image: url("./svg/add.svg") !important;
}

<svg width="16" height="16" xmlns="http://www.w3.org/2000/svg" fill="context-fill" fill-opacity="context-fill-opacity">
  <path d="M14 7H9V2a1 1 0 0 0-2 0v5H2a1 1 0 1 0 0 2h5v5a1 1 0 0 0 2 0V9h5a1 1 0 0 0 0-2z"/>
</svg>

var pref = Services.prefs, chr = "devtools.chrome.enabled", rem = "devtools.debugger.remote-enabled";
if (!pref.getBoolPref(chr) || !pref.getBoolPref(rem)) {
    pref.setBoolPref(chr, true);
    pref.setBoolPref(rem, true);
}

var { BrowserToolboxLauncher } = ChromeUtils.import("resource://devtools/client/framework/browser-toolbox/Launcher.jsm");
BrowserToolboxLauncher.init();

(async n => {
	var menuitem = n("menu_pageInfo").cloneNode(false);
	menuitem.id = "context-" + menuitem.id;
	menuitem.removeAttribute("key");
	n("context-inspect-a11y").before(menuitem);
})(id => document.getElementById(id));

// Этот скрипт можно использовать для создания кнопок с помощью CustomizableUI.createWidget

// Отдельная кнопка about:config с альт.управлением от Vitaliy V.
// https://forum.mozilla-russia.org/viewtopic.php?pid=783542#p783542
try {
    ((id, label, tooltiptext, about_config) => {
        CustomizableUI.createWidget({
            id: id,
            type: "custom",
            label: label,
            tooltiptext: tooltiptext,
            localized: false,
            defaultArea: CustomizableUI.AREA_NAVBAR,
            onBuild: function(document) {
                var win = document.defaultView;
                var toolbarbutton = document.createXULElement("toolbarbutton");
                toolbarbutton.id = id;
                toolbarbutton.className = "toolbarbutton-1 chromeclass-toolbar-additional";
                toolbarbutton.setAttribute("label", label);
                toolbarbutton.setAttribute("context", "false");
                toolbarbutton.setAttribute("tooltiptext", tooltiptext);
                toolbarbutton.setAttribute("image", "data:image/png;base64,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");
                toolbarbutton.addEventListener("click", function(event) {
                    if (event.button == 0) {
                        if (!event.ctrlKey)
                            win.gBrowser.selectedTab = about_config.addTab(win, "about:config",  {
                                relatedToCurrent: true,
                            });
                    }
                    else if (event.button == 2) {
                        event.preventDefault();
                        event.stopPropagation();
                        if (!event.ctrlKey)
                            about_config.openSelectedConfigTab(win);
                        else
                            about_config.openClipboardConfigTab(win);
                    }
                });
                return toolbarbutton;
            }
        });
    })(
        "ucf-open-about-config",
        "about:config",
        "ЛКМ:		 Открыть about:config\nПКМ:		 Искать выделенное\nCtrl+ПКМ:	 Искать из буфера",
        {
            get ClipboardHelper() {
                delete this.ClipboardHelper;
                return this.ClipboardHelper = Cc["@mozilla.org/widget/clipboardhelper;1"].getService(Ci.nsIClipboardHelper);
            },
            openClipboardConfigTab: function(win, clip = "", copy) {
                var filter = this.readFromClipboard(win), nowarn = false, pref = "browser.aboutConfig.showWarning";
                if (copy && clip != filter)
                    this.ClipboardHelper.copyString(clip);
                if (Services.prefs.getBoolPref(pref, false)) {
                    Services.prefs.setBoolPref(pref, false);
                    nowarn = true;
                }
                var browser = win.gBrowser.getBrowserForTab(win.gBrowser.selectedTab = this.addTab(win, "about:config", {
                    relatedToCurrent: true,
                }));
                browser.addEventListener("pageshow", (e) => {
                    var doc = e.currentTarget.contentDocument, input = (doc && doc.querySelector("input#about-config-search"));
                    if (input && filter) {
                        input.value = filter;
                        input.dispatchEvent(new doc.defaultView.Event("input", { bubbles: true }));
                    }
                    if (nowarn)
                        setTimeout(() => {
                            Services.prefs.setBoolPref(pref, true);
                        }, 200);
                }, { once: true });
            },
            openSelectedConfigTab: function(win) {
                var clip = this.readFromClipboard(win);
                win.goDoCommand("cmd_copy");
                setTimeout(() => {
                    this.openClipboardConfigTab(win, clip, true);
                }, 100);
            },
            addTab: function(win, url, params = {}) {
                params.triggeringPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
                return win.gBrowser.addTab(url, params);
            },
            readFromClipboard: function(win) {
                var url = "";
                try {
                    var trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(Ci.nsITransferable);
                    var contxt = ("docShell" in win) ? win.docShell.QueryInterface(Ci.nsILoadContext) : win.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation).QueryInterface(Ci.nsILoadContext);
                    trans.init(contxt);
                    trans.addDataFlavor("text/unicode");
                    var clipboard = Services.clipboard;
                    clipboard.getData(trans, clipboard.kGlobalClipboard);
                    var data = {};
                    trans.getTransferData("text/unicode", data, {});
                    if (data.value) {
                        data = data.value.QueryInterface(Ci.nsISupportsString);
                        url = data.data;
                    }
                } catch (ex) { }
                return url;
            },
        }
    );
} catch(e) {}

// Открытие "about:debugging#/runtime/this-firefox"
// по ПКМ на стандартном значке менеджера дополнений
// https://forum.mozilla-russia.org/viewtopic.php?pid=791976#p791976
(this.opendebuggingruntimethisfirefox = {
    async init(that) {
        await window.delayedStartupPromise;
        var btn = CustomizableUI.getWidget("add-ons-button")?.forWindow(window).node;
        if (!btn) return;
        btn.setAttribute("context", "");
        btn.tooltipText = `ЛКМ:		 Менеджер дополнений\nПКМ:		 Отладка дополнений\nCtrl+ПКМ:	 Политики`;
        var listener = e => {
            if (e.button != 2) return;
            e.preventDefault();
            e.stopPropagation();
            e.stopImmediatePropagation();
            var gb = e.view.gBrowser;
            gb.selectedTab = gb.addTrustedTab(`about:${
                e.ctrlKey ? "policies" : "debugging#/runtime/this-firefox"
            }`);
        };
        btn.addEventListener("click", listener);
        that.unloadlisteners.push("opendebuggingruntimethisfirefox");
        this.destructor = () => {
            btn.removeEventListener("click", listener);
        };
    }
}).init(this);