Bypass Forced Download per Lukas Mai

Some websites force users to download/save certain files, even if Firefox knows how to handle them (e.g. by displaying them directly (HTML, PDF, ...) or by opening them in another program). This add-on completely disables this functionality; i.e. if Firefox knows what to do with a file, it will do it, and all download requests are ignored. (You can still explicitly save files by right-clicking on a link and choosing "Save Link As..." or by using "Save Page" in the Firefox menu.)

Technical details:
A website can force a download by setting the Content-Disposition: attachment header. This add-on intercepts such headers and rewrites them to Content-Disposition: inline, restoring the default behavior.

It is possible to selectively disable this add-on on some sites by editing the add-on settings in the add-on manager (about:addons). The values should be a list of space separated host names (*, **, and ? are supported as wildcards). The patterns are matched against the host a download is coming from. This add-on doesn't tamper with downloads if the host name doesn't match a whitelist pattern ("hosts to run on") or if the host name matches a blacklist pattern ("except for").

? matches a single non-dot (.) character. * matches 0 or more non-dot characters. ** matches 0 or more characters (including dots). For example, the pattern *.example.com matches foo.example.com but does not match foo.bar.example.com, whereas **.example.com matches both.

The default whitelist is ** (bypass forced downloads everywhere). (The default blacklist is subject to change but currently includes some soundcloud and mediafire hosts because you probably do want to start a download if you click on a "download" button on those sites.)