We faced a notable performance regression of maven builds when updating the maven-jar-plugin which is very likely related to the changes in #79.
What we know for sure is that downgrading the plexus-io dependency from 3.4.0 to 3.3.1 removes the issue.

<dependencies>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-archiver</artifactId>
        <version>3.6.0</version>
        <exclusions>
            <exclusion>
                <groupId>org.codehaus.plexus</groupId>
                <artifactId>plexus-io</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <!-- Downgrade plexus-io to 3.3.1 to avoid performance regression during archive build -->
    <dependency>
        <groupId>org.codehaus.plexus</groupId>
        <artifactId>plexus-io</artifactId>
        <version>3.3.1</version>
    </dependency>
</dependencies>

This is a captured stacktrace of the slowed down code path:
at sun.nio.fs.UnixNativeDispatcher.getgrgid(java.base@17.0.7/Native Method)
at sun.nio.fs.UnixUserPrincipals.fromGid(java.base@17.0.7/UnixUserPrincipals.java:125)
at sun.nio.fs.UnixFileAttributes.group(java.base@17.0.7/UnixFileAttributes.java:212)
- locked <0x00000006cbf60f10> (a sun.nio.fs.UnixFileAttributes)
at sun.nio.fs.UnixFileAttributeViews$Posix.addRequestedPosixAttributes(java.base@17.0.7/UnixFileAttributeViews.java:237)
at sun.nio.fs.UnixFileAttributeViews$Unix.readAttributes(java.base@17.0.7/UnixFileAttributeViews.java:385)
at sun.nio.fs.AbstractFileSystemProvider.readAttributes(java.base@17.0.7/AbstractFileSystemProvider.java:94)
at java.nio.file.Files.readAttributes(java.base@17.0.7/Files.java:2084)
at org.codehaus.plexus.components.io.attributes.FileAttributes.(FileAttributes.java:110)
at org.codehaus.plexus.components.io.attributes.FileAttributes.(FileAttributes.java:88)
at org.codehaus.plexus.components.io.resources.PlexusIoFileResourceCollection.addResources(PlexusIoFileResourceCollection.java:163)
at org.codehaus.plexus.components.io.resources.PlexusIoFileResourceCollection.getResources(PlexusIoFileResourceCollection.java:262)
at org.codehaus.plexus.archiver.AbstractArchiver$1.hasNext(AbstractArchiver.java:564)
at org.codehaus.plexus.archiver.zip.AbstractZipArchiver.createArchiveMain(AbstractZipArchiver.java:224)
at org.codehaus.plexus.archiver.zip.AbstractZipArchiver.execute(AbstractZipArchiver.java:202)
at org.codehaus.plexus.archiver.AbstractArchiver.createArchive(AbstractArchiver.java:1028)

We suspect a relation to #79 although we did not look into the details.
Just looking at the stack the cause is likely related to more frequent native FS related calls triggered by execution of java.nio.file.Files.readAttributes from PlexusIoFileResourceCollection.

PS: The used JDK version is not relevant - it at least occurs for both latest OpenJDK 11 and 17 (only tested on Linux, but I'd expect the impact on Windows to be even larger). For a very large project this more than doubled the total build time on some systems - the minimal observed overhead was about 20%, which is still considerable.