Just like in title.
Host can edit revive/incap message for whole server.
Additionally message placeholders for the causer of incap or revive event like:

Player A has been revived by Player B - If player got revived by someone else
Player A has beed revived! - Self revive or revive caused by command

Player A has been incapacitated by Player B / Mob-Name (using [item]) - If player got downed by mob or other player
Player A has been incapacitated - If player got downed by himself, command or natural cause