A 7z archive can be read without extracting it, but how much you get depends on one choice the person who created it made. 7z usually compresses its own index as a single block, and reading that block means decompressing it. File X-Ray is honest about the difference rather than pretending otherwise, and tells you which kind of archive you have.
Scan a 7z archive fileEvery 7z archive gives up its format version, which identifies the generation of the tool that wrote it. Beyond that, the archive falls into one of two cases. When the index is stored uncompressed, File X-Ray reads it in full: the number of files, their names, their per-file timestamps and their Unix permission bits. When the index is packed, which is the more common default, the scan says so explicitly and stops there.
That limitation is a real one and it is stated rather than hidden. Unpacking a compressed index needs an LZMA decoder, which this tool does not ship. It is worth being clear that a packed index is not an encrypted one: the archive is not hiding its contents from you, the listing is simply compressed, and any 7z program on your own machine will show it. The scan draws that distinction so a packed index is never mistaken for a protected one.
When the listing is readable, the Unix permission bits are the interesting part. A 7z built on Linux stores each file's Unix mode in the high half of its Windows attribute word, so the archive records the permissions of the files and, by implication, the platform of the machine that made it. A world-writable or executable bit surviving inside a distributed archive is a genuine finding.
File X-Ray also flags entries whose names look sensitive, because in an archive the filename is often the disclosure. A listing that names a key file, a credential store or a private directory tells you something before anything is extracted.
This is a selection. The full field manual documents the fields read from each format.
You can read its header here. File X-Ray reports the format version for any 7z, and when the archive stores its index uncompressed it also lists the files, their timestamps and their Unix permissions. It does not extract file contents.
Because most 7z archives compress their index as a single block, and decompressing it needs an LZMA decoder this tool does not ship. That is a limitation here, not a property of your file. The archive is not encrypted and nothing is hidden; a 7z program on your own machine will show the listing.
When the listing is readable, a 7z built on Linux carries each file's Unix mode in the high half of its attribute word, so the archive records both the file permissions and the fact that it was created on a Unix-like system.
No. Rewriting one would mean re-encoding the index with an LZMA encoder this tool does not ship, and there is no 7z implementation available here to confirm a rewritten copy still opens. Returning an archive that might not extract is the wrong trade. 7z files are inspected here, not modified.
No. Everything is read in your browser and the file never leaves your device.
File X-Ray reads 7z archive files entirely in your browser - the file never leaves your device. This format is inspected, not modified. Scan a file now.