Tab Mix Plusのセッションファイルをインポートするのは可能でしょうか？前からはそっちを使っていましたがつい最近動作がおかしくなりこちらに移行するのを決めましたけど、今Tab Mix Plusではなぜか保存してるタブの1割程度しか復元できない状態ですから、もし変換が可能ならぜひ試してみたいです。
ちなみにブラウザはWaterfox使っています。
不慣れな日本語ですみません。

It saved my life a few times already. A few months ago firefox started crashing and losing all tabs on linux, and after I installed this addon I had a few crashes that I survived and had a way to restore all my tabs. A real life saver.

Frequently looses tabs in the middle (not the oldest nor the recent one) of list. So it`s not noticeable at firefox startup that tabs are lost if 150+ tabs are opened. What`s even worse is that tabs disappear not in a whole chunk but in few chunks in the middle. Lets say we have 150 tabs. So it`s not tabs 35-75, for example that are lost, but rather tabs 35-40, 60-70 and 90-100 will be gone. So this is not noticeable at first glance. Review is from 1 september 2019 version, as i have changed my previous review as i wanted to support the author and expected better resiliency.

I've only used this for a few weeks but I feel like this add-on has changed the way I browse already. It's wonderful to save sessions for different purposes, like one session of looking at Emulation websites, one session for seeing sites about a certain game/show or another session for my work/email. No longer do I have to keep one of each around to switch to a different kind of browsing and have the associated memory usage. I can open my browser to a single new tab and use session manager to find the session I want to use. I give it 4 instead of 5 due to a IndexDB issue which thankfully solved itself upon browser reboot, it hasn't popped up again but it does pose a reliability issue for the add-on.

Highly recommended, should be a feature for stock browsers in the future IMO.

「素晴らしい、感謝しきれない。」
ただ以下のバックアップの読み込み方法は不明。
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バックアップを保存する
ブラウザの起動時にセッションのバックアップファイルを作成し，ダウンロードフォルダに保存します。

As one of the early adopters, I have been using this add-on from the time Quantum disabled "Sessions Manager". Over a year, this add-on has come close to the functionality of the "sessions manager" add-on by Michael Kraft. I must commend the dev, sienori on his relentless efforts through regular updates in helping the Firefox community. Kudos to the work! The only grouse I have though is that sometimes, I get the IndexDB erroe which surprisingly, automatically resolves itself in a few days. Can't blame for it. Have a good one dev! Cheers.

Frequent updates & nice, clean interface. Haven't had any problems.