This is the 13833rd most frequent Russian word.
обгоревшего
"Обгоревшего" means "burnt" or "scorched" in English.
Here, 'обгоревшего' describes the condition of the old document, indicating it has been partially burnt.
Я нашел пергамент из обгоревшего старинного документа.
I found parchment from a burnt ancient document.
In this sentence, 'обгоревшего' depicts the state of the tree in the forest affected by fire.
Он рассказал историю об обгоревшего дерева в лесу.
He told a story about a scorched tree in the forest.
'Обгоревшего' is used here to describe the burned condition of the bread, specifically its surface.