Apache Ant Source Code Files are inside the Apache Ant source package file like apache-ant-1.10.10-src.zip. Unzip the source package file and go to the "src/main" sub-directory, you will see source code files.

Here is the list of Java source code files of the Apache Ant 1.10.10 in \Users\fyicenter\apache-ant-1.10.10\src\main:

⏎ org/apache/tools/ant/types/selectors/ExtendFileSelector.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package org.apache.tools.ant.types.selectors;

import org.apache.tools.ant.types.Parameterizable;

/**
 * This is the interface to be used by all custom selectors, those that are
 * called through the <custom> tag. It is the amalgamation of two
 * interfaces, the FileSelector and the Parameterizable interface. Note that
 * you will almost certainly want the default behaviour for handling
 * Parameters, so you probably want to use the BaseExtendSelector class
 * as the base class for your custom selector rather than implementing
 * this interface from scratch.
 *
 * @since 1.5
 */
public interface ExtendFileSelector extends FileSelector, Parameterizable {

    // No further methods necessary. This is just an amalgamation of two other
    // interfaces.
}

⏎ org/apache/tools/ant/types/selectors/ExtendFileSelector.java

Or download all of them as a single archive file:

File name: apache-ant-1.10.10-fyi.zip
File size: 2392938 bytes
Release date: 2021-04-17
Download 

⇒ ant-1.8.0.jar - Apache Ant

⇐ Download Apache Ant Source Package

⇑ Apache Ant - Java Build Tool

⇑⇑ Java/JAR Tools