for xiaomi ra67 i use miwifi_ra67_firmware_63805_1.0.16 firmware wich is openwrt version 18.06.x
i have ssh access to router and want to install package using opkg
It appears you are using firmware that is not from the official OpenWrt project.
When using forks/offshoots/vendor-specific builds that are "based on OpenWrt", there may be many differences compared to the official versions (hosted by OpenWrt.org). Some of these customizations may fundamentally change the way that OpenWrt works. You might need help from people with specific/specialized knowledge about the firmware you are using, so it is possible that advice you get here may not be useful.
Ask for help from the maintainer(s) or user community of the specific firmware that you are using.
Provide the source code for the firmware so that users on this forum can understand how your firmware works (OpenWrt forum users are volunteers, so somebody might look at the code if they have time and are interested in your issue).
If you believe that this specific issue is common to generic/official OpenWrt and/or the maintainers of your build have indicated as such, please feel free to clarify.
10x for quick answer!
1.as we can see from /etc/opkg/distfeeds.conf this snapshot has been hosted onhttp://downloads.openwrt.org. I don't know what the principle is. perhaps it was removed at the request of xiaomi.
2. I can't share anything valuable from this distro. almost everything is compiled including lua scripts