This extension collects nothing and transmits nothing.

WHAT IT ACCESSES

It reads the content of pages on x.com and twitter.com. It does this by
observing the responses those pages have already requested for themselves the same data your browser has already received and is displaying to you.

WHAT IT SENDS

Nothing. The extension makes no network requests. It contacts no server, has
no analytics, no telemetry, and no error reporting. Its manifest declares
data_collection_permissions: none.

WHERE DATA GOES

Converted Markdown goes to two places, both under your control and both chosen
by you: your clipboard, and a file in your Downloads folder. Nowhere else.

WHAT IS STORED

Captured post content is held in memory only, for the lifetime of the page,
and is discarded when you navigate away or reload. Nothing is written to
extension storage or to disk except the file you asked for. Your settings
export format preferences and collection limits are stored in Firefox's
extension storage and contain no post content.

An optional Debug mode, off by default, retains the last few raw responses in
memory so they can be saved as a test fixture. This is a developer feature; it
still sends nothing anywhere, and the file it produces is written only when you
click to produce it.

PERMISSIONS

• x.com and twitter.com access to read the page you are exporting
• downloads to write the .md file
• clipboardWrite to copy the result; write-only, the extension never reads
your clipboard
• storage for your settings only

Source code: https://github.com/YouKyi/x-to-markdown