Macbook EFI parition after reFind
You can delete everything from the EFI partition if you wish. OS X will recreate what it needs when the operating system starts. Basically, OS X copies the Firmware.scap file from the boot partition to the EFI  partition.

The files and folders marked below for deletion are not part of OS X.

BOOTLOG                            &lt;---- Delete
BOOTLOG.OLD                        &lt;---- Delete
screenshot__001.bmp                &lt;---- Delete
screenshot__002.bmp                &lt;---- Delete
EFI/
    APPLE/ 
        CACHES/
            CAFEBEEF/
                (empty)
        EXTENSIONS/
            Firmware.scap
        FIRMWARE/
            MBP91_00D3_B0D_LOCKED.scap
    Ubuntu/                             &lt;---- Delete (Part of Ubuntu)
    tools/                              &lt;---- Delete (Part of rEFInd)
        gptsync_x64.efi                 &lt;---- Delete (Part of rEFInd)
    reFind/                             &lt;---- Delete (Part of rEFInd)


The rest of the files were put there by OS X or related software.