Learn Portuguese (Portugal): Se calhar o objeto pessoal está nesta secção. - Maybe the personal object is in this section.

This is a special rule. Even though se calhar means 'maybe' and expresses doubt or probability, it is always followed by the normal indicative mood. If you wanted to use talvez (which also means maybe/perhaps), then you would need the subjunctive (talvez o objeto pessoal esteja...).

Why use está instead of é if the object permanently belongs in that section?

In Portuguese, the verb estar is always used for the physical location of objects, buildings, or people. It does not matter if the location is temporary or permanent; stating where something is physically located always calls for estar.

Why is the word nesta used here instead of em esta?

The word nesta is a mandatory contraction. Whenever the preposition em (in/on/at) comes directly before the demonstrative esta (this), they must combine into nesta. Saying em esta sounds unnatural and is grammatically incorrect in Portuguese.

Why does secção have a 'cç' but objeto doesn't have a 'c' before the 't'?