This was posted on JP side probably some of you already knew, some didn't... I just translated and posting it for reference for those that didn't know.

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copy/paste from my translation thread
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Quote Originally Posted by Triairy View Post
こんばんは。
Good evening,

かばう対象と自身のMP回復などが付けば、ナイトのMP問題改善かつ
ソーサラーとの連携で戦略的価値がググっと上がりそうですが。
For "Cover" would be helpful if it added restore MP effect to fix the Paladin's MP issue and help plan out strategy with sorcerers.
ちょっとわかりにくいガラントサーコートの「かばう効果アップ」ですが、「かばう」自体の「効果」がアップするのではなく、「かばう」に新たな効果が付与されるボーナスになります。
For the effect added on the Gallant Surcoat "Enhances Cover" - this doesn't increase the effect of cover but actually add new bonus effect to "Cover"

具体的には、「かばう」効果中に受けたダメージに応じた「MP回復効果」を得られます。
このダメージは「かばう」によって肩代わりしたダメージだけでなく、ナイト自身が直接受けたダメージも含まれます。
Specifically when "Cover" is in effect and when you take damage it adds "Restore MP effect" For this damage not only does it include the damage you take over from others but damage you take yourself as well.

ぜひ一度ガラントサーコートを装備して試してみてください。
Please try out the Gallant Surcoat next time
Right after this post people said it's old school to hide effect info for stuff like this and to have it indicated in the gear info instead of _____ effect up which we don't know what it actually does until someone figures out.