My script for me (Debian/sid):

#!/bin/sh
# https://packages.ubuntu.com/cosmic/amd64/chromium-codecs-ffmpeg-extra/download

lib_opera=/usr/lib/x86_64-linux-gnu/opera
dl_url=http://security.ubuntu.com/ubuntu/pool/universe/c/chromium-browser/
dl_package=chromium-codecs-ffmpeg-extra
dl_deb=_73.0.3683.86-0ubuntu0.18.10.1_amd64.deb  # modify the version number

tmpfolder=/tmp/${dl_package}
mkdir -p ${tmpfolder}

wget ${dl_url}${dl_package}${dl_deb} -P ${tmpfolder}
cd ${tmpfolder}

ar -x ${dl_package}${dl_deb}
tar -xJf data.tar.xz

# with sudo
sudo cp ${tmpfolder}/usr/lib/chromium-browser/libffmpeg.so ${lib_opera}/libffmpeg.so

# without sudo but run the script as root
# cp ${tmpfolder}/usr/lib/chromium-browser/libffmpeg.so ${lib_opera}/libffmpeg.so

cd ..
rm -r ${tmpfolder}

DNAWIZ-26931 still not fixed → https://forums.opera.com/post/142021

@leocg I have, but my comment have been deleted

I get newsfeed from Opera blogs in this feed, the address is an HTTP link.

If I write an answer in this blog but go in via an HTTPS address, the post is gone (all)
Example:
https://blogs.opera.com/desktop/2018/03/opera-53-0-2893-0-developer-update/
http://blogs.opera.com/desktop/2018/03/opera-53-0-2893-0-developer-update/
A blog post and two different commentary trees.

This is stange, better only HTTPS and all HTTP redirect to https.
And my comments from this blog have been deleted…

update-alternatives --display gnome-www-browser
gnome-www-browser - manual mode
  link best version is /usr/bin/opera-developer
  link currently points to /usr/bin/opera-developer
  link gnome-www-browser is /usr/bin/gnome-www-browser

update-alternatives --display x-www-browser
x-www-browser - manual mode
  link best version is /usr/bin/opera-developer
  link currently points to /usr/bin/opera-developer
  link x-www-browser is /usr/bin/x-www-browser

Workaround for me, i edit the $HOME/.local/share/applications/exo-web-browser.desktop

[Desktop Entry]
Version=1.0
Type=Application
Exec=x-www-browser %u
Icon=web-browser
StartupNotify=true
Terminal=false
Categories=Network;X-XFCE;X-Xfce-Toplevel;
OnlyShowIn=XFCE;
X-XFCE-MimeType=x-scheme-handler/http;x-scheme-handler/https;
Name=Web Browser
Comment=Browse the web
Hidden=true

Original

Exec=exo-open --launch WebBrowser %u

Since Opera 53.0.2885.0 developer (also Opera 53.0.2893.0) i get a system message when opening a URL if it comes from an external program (IRC link, help link from LibreOffice, etc.).

German:

Der vorgegebene Internetnavigator konnte nicht gestartet werden.
Eingabe-/Ausgabefehler

English:

Failed to execute default Web Browser.
Input/output error

Site opens, but with the stupid system dialog.

No dialog with Opera developer 53.0.2880.0, Opera stable, Firefox, Vivaldi
The dialog only opens if Opera Dev ⋝ 53.0.2885.0 is the default browser.
command line:
exo-open URL with dialog (exo-open starts the default browser)
opera-developer URL without dialog

OS: Siduction 64bit
DE: Xfce 4.12

Can anybody confirm that, or what is the mistake?

With Opera developer 51.0.2830 works gpu, all my issues from above have been fixed.

@loup001
Do you have NVIDIA, if so, can you check on opera:gpu if the hardware support is enabled?
And how does the http://slither.io site work for you or very slow?

With me the GPU support Opera Developer 51.0.2809.0 is corrupt (see my posting above).
My result from opera:gpu: Opera_51.0.2809.0_gpu.pdf

OS: Siduction 64bit, NVIDIA 9600 GT (nvidia-legacy-340xx-driver)

@angrypenguin said in New Opera developer 51:

So, try go to opera:flags and enable this flag - Override software rendering list. Restart browser and check again.

Hi @angrypenguin thanks for the tip, but there not help.
And i have previously tested with command line option.
opera-developer --ignore-gpu-blacklist

I have no more idea.
What is the significant modify difference (program code) between Opera 51.0.2796.0 and 51.0.2809.0?

Hi @l33t4opera

$ lsmod | grep nvidia
nvidia              10559488  43
drm                   360448  3 nvidia
i2c_core               57344  4 nvidia,i2c_i801,psmouse,drm

$ glxinfo | grep direct
direct rendering: Yes
    GL_EXT_depth_bounds_test, GL_EXT_direct_state_access,
    GL_EXT_depth_bounds_test, GL_EXT_direct_state_access,

$ grep glx /var/log/Xorg.0.log 
[    35.598] (II) LoadModule: "glx"
[    35.647] (II) Loading /usr/lib/xorg/modules/linux/libglx.so
[    38.115] (II) Module glx: vendor="NVIDIA Corporation"

In browser settings the Hardware acceleration was enable.
The command line option did not help.

No problem with:
Opera Dev
51.0.2781.0
51.0.2796.0
broken:
51.0.2802.0
51.0.2809.0

And yes, i testing with new profile.