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Install

Foretaste for Firefox

Right-click a file link, choose Open with Foretaste, and it opens. The Firefox add-on is published and free, and it is built from the same source as the other two.

Get Foretaste for Firefox See what it opens

On the Firefox Add-ons site now. The button above opens the official listing, which is the only place to install it from.

01

What it does

  • Opens a file from a link. Right-click it and choose Open with Foretaste, or click the marker beside the link.
  • Lists a ZIP archive without downloading it, and opens one file from inside.
  • Reads the file on your own machine. Nothing is uploaded, to us or to anyone.
  • Saves the file to disk, in every format, including the ones it cannot open, without needing access to the site.
  • Asks for website access once, when you install it. Never again, and never per site.

02

What it opens

7

Documents

.pdf .docx .odt .ott .pptx .odp

 6

Spreadsheets and tables

.xlsx .xls .ods .ots .csv .tsv

 19

Archives

.zip .tar .gz .tgz .zst .tzst

 146

Text, code and data

.txt .log .md .markdown .json .jsonl

 21

Pictures and media

.jpg .jpeg .png .gif .webp .avif

 9

Books, fonts and subtitles

.epub .ttf .otf .woff .woff2 .srt

 4

Calendars and contacts

.ics .ifb .vcf .vcard

What each one actually shows you, and where it stops

03

What it asks Firefox for, and why

This is the full list. Adding one is a deliberate decision, so the list is short and it stays short.

Permission Why it is needed
contextMenus To put "Open with Foretaste" on the right-click menu.
downloads To save a file to disk. This needs no site access, which is why saving is never blocked, on any format.
storage To keep your settings, your licence key and the page’s file list on your device.
scripting To read the addresses of file links, and to put the link markers beside them. You choose whether those appear everywhere, everywhere except a list, or only on a list.
activeTab To read the address of the tab the panel is open over, and nothing else on it.
host access (all sites) To fetch the file behind the link you clicked. Your browser asks for this when you install Foretaste, and grants it there - a file is routinely served from a different address than the page it was linked on, so there is no smaller permission that works. The reading happens on your machine; nothing about the file is sent anywhere.

Note what is not there: no access to your browsing history, no access to your tabs, no cookies, and nothing that reads what you do on a page. Website access is asked for once, when you install it, and it buys one thing: fetching the file behind the link you clicked.

04

How this build stands today

Firefox needs a Manifest V2 package, so it is built separately from the same code. It goes through the same unit tests as the Chrome build, it was reviewed by Mozilla before it was listed, and the manifest differences Firefox needs are in it, including the way a Manifest V2 add-on has to ask for a site permission.

It has not been through the format-by-format pass Chrome has. That pass is somebody sitting down and opening one file of every kind, and it has only been done in Chrome. The two parts most worth telling us about are the panel that opens over a page and the 7z and RAR reader, because those lean on manifest keys that differ between the two builds.

If something behaves differently here, say so at hello@foretaste.page and it will be fixed and written down. The Chrome build is still the one every manual test was run against.

Said here rather than discovered by you after installing it.

05

Installing it

  1. Open the Firefox Add-ons site listing and choose "Add to Firefox".

    Your browser will show you the permission list above before it installs anything.

  2. Grant the access your browser asks for, once.

    It is asked for at install and never again, and never per site. The reason is on the privacy page: a download is routinely served from a different address than the page it was linked on, so being asked per site would mean being asked forever.

  3. Right-click a file link and choose "Open with Foretaste".

    You can also open files in a new tab instead of a panel, from Settings, if that suits you better.