On 2016-05-06 08:24, Yuri Khan wrote:
> No, Gmail sends normal “Content-Type: multipart/alternative”
> messages, where the first alternative is text/plain and uses
> conventional “>” quoting, and the second alternative is text/html,
> optionally encoded as quoted-printable, with <blockquote> quoting.
> The messages are valid w.r.t. RFC 2822 and RFC 2045, and the
> text/html payload is loosely well-formed HTML5.

I don't think so. When I look at the source of Kaushal's messages, the '>' character is missing on the first line of each quoted section (see for example his message <CAFyQvY0-gMVfOTbCvCm7JUZEf2NaWKkfn-EDk2MSM_WTvJVKQw@mail.gmail.com>). Thus what should be rendered as the following is actually as shown below in the message body:

(Intended rendering, as suggested by the blockquotes in the HTML version:)

    > I suggest to change/add the docstring accordingly, because the new
    > behavior is a radical change.

    > I could provide a 'patch' for that[1]

    That's great!

    > , but not sure about the structure of
    > that patch

(Actual rendering:)

    >
    > I suggest to change/add the docstring accordingly, because the new

    behavior is a radical change.
    >
    > I could provide a 'patch' for that[1]


    That's great!

    , but not sure about the structure of
    > that patch

Or is there an issue with Thunderbird's source rendering?

Clément.