New

A link on combination rules. Now they can carry a link too, and you choose whether every word in the rule becomes clickable or just one word you pick. Either way the link is only live while the rule is actually met.

An indicator for links. A checkbox on every list, word rule, pattern rule and combination rule puts a small marker on the word, so you can see it is clickable before you click it. It sits in a different corner from the tooltip marker, so a word carrying both a note and a link shows both.

A warning before a pattern rule that can freeze a page. A pattern with one quantifier inside another — (a+)+, (\d+)+, (\s\w+)$ — can take minutes to resolve on ordinary text, and nothing can interrupt it once it starts. Saving one now explains that and offers a safety limit: with it on, the rule stops running for the rest of a page as soon as one block of text costs it too much. It is a warning and a choice, not a block.

Seventeen theme presets, up from ten: Obsidian, Monolith, AAA Dark, Tokyo Night, Dracula, Amethyst, Gruvbox, Everforest, Terminal, Sepia, Terracotta Desert, Solarized Light, Sakura, Biophilic, Oceanic, Corporate Memphis and Glassmorphism. Where a name has a well-known palette, that palette is what you get.

Improved

Presets no longer touch your typography or your shape. Picking a colour theme used to quietly reset your font, type scale, letter spacing, corner radius, border width and shadow back to the defaults. Presets are colours now, and everything you set stays set.

A preset applies the moment you click it. The accent colour used to wait for Save, so you could pick a new theme and still be looking at the old one's accent. The same bug meant switching between Dark and Light discarded an accent you had picked but not yet saved.

Switching language applies the moment you click it. The whole popup re-translates on the spot instead of waiting for Save, and Cancel puts it back.

Density respects Cancel. Picking a density used to save itself immediately, so cancelling out of Settings left the change behind.

Fixed

Changing only a highlight's background opacity did not count as an unsaved change, so leaving the editor threw it away without asking. It asks now.

Reset to global theme really resets it. It cleared the override groups but left the theme mode and the accent wherever a preset had put them, so picking a light preset and then resetting left unreadable labels and buttons.

A damaged backup can no longer stop highlighting. A list whose words had been turned into numbers by an outside editor imported without complaint and then stopped the extension marking anything at all, on every page, until the browser was restarted.

Pasting a malformed preset tells you so instead of failing silently.

The export message claimed there were ten built-in presets. It no longer claims a number.
On Firefox for Android the popup opened at desktop width and was scaled dow

New
- Temporary highlights from the right-click menu. Select any text, right-click, and "Highlight temporarily on every page" marks it everywhere until you close the browser. Up to five at a time, each its own colour, shown as chips in the popup so you can drop any of them with one click. Nothing is added to a list and nothing is saved past the session. It applies right away.

• Activity report. A second report next to the inactivity one, showing the words, rules and lists that fire on the most pages. Counted once per page, not once per occurrence, with a reset and a "counting since" date.
• Custom notification titles. Lists, word rules, pattern rules and combination rules can each carry their own notification title. The matched text stays as the body, so it is still the part you can copy.
• Delete all my data. A new button in Settings → Backup wipes every list, folder, rule, preset and setting from the device and the account, behind a confirmation.

Improved
- The three fuzzy sensitivities are now Strict, Moderate and Wide instead of numbers pretending level 1 was exact. Very short words no longer match at all, and the preview actually changes across the three levels.

• Backup and Help & Support were rebuilt to fit without scrolling. Export's categories are chips instead of a long checkbox list, Backup is one row of three buttons, and the help links are a grid.
• The colour picker is fully keyboard-operable — arrows, Shift+arrows, Page Up/Down, Home/End and Escape — with labels for screen readers.
• Contrast fixes on input borders, dropdowns and muted icons, in both themes.
• The review link now opens the right store.
• Font licences are bundled with the extension.

Removed
- The "Experimental features, off by default." line.

Changelog: https://sites.google.com/view/highlight-mxm/changelogs/firefox-changelogs/232Firefox-hOVRhSBP

*** Five new styles ***
Strikethrough, double underline, dotted underline, ALL CAPS and all lowercase join bold, italic and underline, in both the word-list editor and the pattern-rule editor. The full row, in order: bold, italic, underline, strikethrough, double underline, dotted underline, ALL CAPS, all lowercase. Strikethrough combines freely with any underline style. The three underline styles are mutually exclusive, so picking one clears the others, and ALL CAPS and all lowercase are mutually exclusive with each other. Casing changes how a match is displayed only — the underlying text, and anything copied from it, keeps its original casing.

*** Background opacity ***
Every list and every pattern rule gets a 0–100% opacity for its highlight fill, so a colour can sit behind text as a wash instead of a solid block. It is independent of the existing “no background” toggle, which still exists for text-only styling.

*** A colour picker built in ***
The browser’s native picker is gone everywhere in the extension, replaced by one built in: a saturation/value square, a hue slider, and a hex field.

*** Opacity on the pickers that need it ***
An opacity slider appears on the two pickers where opacity applies.

https://sites.google.com/view/highlight-mxm/changelogs/firefox-changelogs/231Firefox-M1x8R5v3

Your setup follows your Firefox account:
Lists, folders, word rules, combination rules, pattern rules, theme presets and settings are stored in your Firefox account, so signing in on another computer brings them with you. It is on by default and needs no setup beyond being signed in to Firefox. The record of when each word was last seen — what the inactivity report reads — stays on the device, since it describes what this browser has encountered rather than how Highlight is set up.

A switch, in Settings → Backup:
Sync across my devices turns it off and back on whenever you like. Turning it off moves everything back onto this device and clears what was stored in your account; turning it on puts it back. Nothing is lost either way, and the line underneath always says where things currently stand.

Large lists stay put instead of failing:
Firefox caps a single synced item at about 8KB and the whole account at about 100KB — a list of 400-500 words reaches the first cap on its own. Rather than let a save fail, anything that doesn't fit is kept on this device and marked local only on its row. The rest keeps syncing. Export/Import still moves the oversized ones by hand.

The total limit is handled too:
Items that each fit can still exceed the account's overall ceiling together, and no size check can see that coming. When Firefox refuses a write, that item falls back to this device rather than being dropped — so a large collection degrades one list at a time instead of breaking.