hg-git is a mercurial plugin that is required by mercurial users to work with git repos. Below is a How-To to get it to work on Ubuntu or any similar linux distro e.g Pop OS.

Install pip3

sudo apt install python3-pip

Clone the hg-git repo (from the FOSS site) in your /tmp directory

cd /tmp
hg clone https://foss.heptapod.net/mercurial/hg-git

Install the cloned repo using pip3

pip3 install hg-git/

Enable the hg-git extension globally in the global .hgrc

vi ~/.hgrc

Add the following in the [extensions] block:

[extensions]
# uncomment the lines below to enable some popular extensions
# (see 'hg help extensions' for more info)
hgext.bookmarks = 
hggit = 

In your local mercurial repo, add a reference to a remote git repo, for example:

vi .hg/hgrc

Add a reference to a git repo. Replace your_username and your_git_repo with your respective variables. I’m using bitbucket as an example below:

[paths]
default = git+ssh://git@bitbucket.org/your_username/your_git_repo.git

Fetch changes from a remote git repo

hg pull

To push a local mercurial repo to an online git repo, first add a bookmark

hg bookmark -r default master

Then you can push your changes

hg push

(Optional) To exclude viewing diffs from a certain file

hg diff --exclude yarn.lock